Fpr1 antagonist derivatives and use thereof

ABSTRACT

A dipeptide derivative as formyl peptide receptor 1 (FPR1) antagonist is provided. The dipeptide derivative is represented by formula (I), 
     
       
         
         
             
             
         
       
         
         
           
             wherein: 
             the chiral centers in formula (I) are S and R configurations respectively; 
             each of RK and RT is selected from a group consisting of a hydrogen, a hydroxyl group, a C 1 -C 4  alkyl-substituted hydroxyl group, a C 1 -C 4  alkoxyl group, a carboxylic acid group, a C 1 -C 4  alkyl nitrile-substituted, C 1 -C 4  alkyl-substituted or C 1 -C 4  alkoxyl-substituted amido group, a C 1 -C 4  alkyl-substituted ester group and a benzoyl group having a C 1 -C 4  alkyl-substituted benzene ring; and each of RM and RS is selected from a group consisting of a hydrogen, a hydroxyl group, a phenyl group, a pyridinyl group, a carboxylic acid group, a C 1 -C 4  alkoxyl substituted ester group, and a benzoyl group having a hydroxyl-substituted, a halogen-substituted, a C 1 -C 4  alkoxyl-substituted or a C 1 -C 4  alkyl-substituted benzene ring.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY

This application claims the benefit of Taiwan Patent Application No.102136641, filed on Oct. 9, 2013, at the Taiwan Intellectual PropertyOffice, the disclosures of which are incorporated herein in theirentirety by reference.

FIELD OF THE INVENTION

The present invention relates to the use of dipeptide derivatives, suchas N—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters and theirapplications in diseases or symptoms associated with formyl peptidereceptor 1 (FPR1) activities.

BACKGROUND OF THE INVENTION

Formyl peptide receptor (FPR) belongs to the family of G-protein coupledreceptors (GPCRs). The FPR family can be divided into three classes,FPR1, FPR2 and FPR3. FPR2 and FPR3 are classified into FPR-likereceptors, wherein FPR2 is also known as FPR-like receptor 1 (FPRL-1)and FPR3 is also known as FPR-like receptor 2 (FPRL-2). FPR1 is found inmonocytes, polymorphonuclear leukocytes and immature dendritic cells,and FPR2 is found in liver cells, lung cells, spleen cells, Tlymphocytes, monocytes and polymorphonuclear leukocytes. FRP1 and FPR2are two members of the FPRs, which are found in human neutrophils.Formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP or fMLF) is a N-formylpeptide, which is a chemo-attractant bound to FPR1 and further totrigger a cell activating response to release toxic substances orproteases. The affinities of fMLF toward the three FPR receptors aredifferent, and the affinity is higher for FPR1. The activation of FPR1elicits multiple signaling pathways, such as calcium, phospholipase C,phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinases(MAPKs), and protein tyrosine kinases (PTKs), which cause neutrophilsactivation for migration, respiratory burst, and degranulation. Thussome literature reported that inhibition of activation of neutrophilscould be as target for treatment of inflammation induced by neutrophils,such as asthma, rheumatoid arthritis, psoriasis, sepsis, myocardialischemia/reperfusion injury, acute respiratory distress syndrome,chronic obstructive pulmonary disease, etc. Recent studies indicatedthat FPR1 is not only involved in infection and the inflammatoryprocess, but also playing a role in promoting tumor progression. Inparticular, FPR1 is able to interact with endogenous annexin AI, andthen transactivate EGFR in glioblastoma cells to mediate cell migrationand growth. Therefore, FPR1 also is a therapeutic target for treatinghuman glioblastoma.

In 2010, Movitz and his co-workers showed that a peptide with a Trp-Phefragment in the C-terminal was able to selectively bind to the FPR1receptor; however, this dipeptide alone was unable to inhibit theneutrophil respiratory burst induced by FMLP, and the associatedgeneration of superoxide anion (O₂ ^(•-)) or radicals.

Additionally, a search Orbit and Google patent databases, EP 2490021 A1and WO 2012112048 A1 recited a series of dipeptide derivativescontaining chemical formulas such as H—X₁-X₂—OH, which can be used aspattern recognition receptors and the signal transduction pathway forG-protein coupled receptors, wherein configurations of two amino acidsare both S (or R) configurations.

US 20130109866 A1 and WO 2013062947 A1 disclose that a series ofderivatives of N-terminal amino acids containing urea groups canregulate a FPRL-1 receptor, which is an alias for an FPR2 receptor.

WO 2012074785 A1, WO 2013070600 A1, U.S. Pat. No. 8,440,684 B2, WO2013009543 A1, US 20120238628 A1, US 20110319454 A1 and WO 2012109544 A1all disclose technical solutions for regulating compounds about FPRL-1receptors.

Based on the above, FPR1 antagonists can regulate inflammation, cancersand other diseases, but no FPR1 antagonist is used clinically.Therefore, the development of an FPR1 antagonist is currently veryimportant.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a method fortreating neutrophil inflammatory disorders with an antagonist of formylpeptide receptor 1 (FPR1) is provided. The method includes providing aderivative of N—(N-aroyl-L-tryptophanyl)-D-phenylalanine represented byformula (I), wherein: the chiral centers in formula (I) are S and Rconfigurations respectively; each of RK and RT is selected from a groupconsisting of a hydrogen, a hydroxyl group, a C₁-C₄ alkyl-hydroxylsubstituted (C₁-C₄ alkyl-OH) group, a C₁-C₄ alkoxyl group, a carboxylicacid group, a C₁-C₄ alkyl nitrile-substituted (CONHC₁-C₄alkyl-CN) group,or C₁-C₄ alkyl-substituted (CONHC₁-C₄ alkyl) or C₁-C₄alkoxyl-substituted (CONHC₁-C₄ alkoxyl) amido group, a C₁-C₄alkyl-substituted ester (COOC₁-C₄ alkyl) group and a benzoyl grouphaving a C₁-C₄ alkyl-substituted benzene ring; and each of RM and RS isselected from a group consisting of a hydrogen, a hydroxyl group, aphenyl group, a pyridinyl group, a carboxylic acid group, a C₁-C₄alkoxyl substituted ester group, and a benzoyl group having ahydroxyl-substituted, a halogen-substituted, a C₁-C₄ alkoxyl-substitutedor a C₁-C₄ alkyl-substituted benzene ring.

In accordance with another aspect of the present invention, a dipeptidederivative is provided. The dipeptide derivative is represented byformula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively;    -   each of RK and RT is selected from a group consisting of a        hydrogen, a hydroxyl group, a C₁-C₄ alkyl-substituted hydroxyl        group, a C₁-C₄ alkoxyl group, a carboxylic acid group, a C₁-C₄        alkyl nitrile-substituted, C₁-C₄ alkyl-substituted or C₁-C₄        alkoxyl-substituted amido group,    -   a C₁-C₄ alkyl-substituted ester group and a benzoyl group having        a C₁-C₄ alkyl-substituted benzene ring; and    -   each of RM and RS is selected from a group consisting of a        hydrogen, a hydroxyl group, a phenyl group, a pyridinyl group, a        carboxylic acid group, a C₁-C₄ alkoxyl substituted ester group,        and a benzoyl group having a hydroxyl-substituted, a        halogen-substituted, a C₁-C₄ alkoxyl-substituted or a C₁-C₄        alkyl-substituted benzene ring.

In accordance with a further aspect of the present invention, adipeptide derivative is provided. The dipeptide derivative isrepresented by formula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively;    -   RK is selected from a hydrogen; RS is selected from a        methylphenyl group;    -   RM is selected from a phenyl group; and    -   RT is selected from C₁-C₄ alkoxyl-substituted ester group.

In accordance with further another aspect of the present invention, adipeptide derivative is provided. The dipeptide derivative isrepresented by formula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively;    -   RK is selected from a hydrogen;    -   RS is selected from a methyl-C₆-cycloalkyl group;    -   RM is selected from a phenyl group; and    -   RT is selected from C₁-C₄ alkyl-substituted ester group.

In accordance with further another aspect of the present invention, amethod for treating a neutrophil inflammatory disorders with anantagonist of Formyl Peptide Receptor 1 (FPR1) is provided. The methodincludes providing a derivative ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters represented byformula (II), wherein:

the chiral centers in formula (II) are S and R configurationsrespectively;

R₁ is one selected from a group consisting of a hydrogen, a hydroxylgroup and a methoxy group;

R₂ is one selected from a group consisting of a non-substituted phenylgroup, a mono-substituted phenyl group, a di-substituted phenyl group,or a tri-substituted phenyl group, a pyridinyl group and a C₄-C₆cycloalkyl group;

R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is one selected from a group consisting of a hydroxyl, a C1-C4alkoxyl and a glycin-nitrile groups.

In accordance with further another aspect of the present invention, amethod for treating a neutrophil inflammatory disorder with anantagonist of formyl peptide receptor 1 (FPR1) is provided. The methodincludes providing a derivative ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters represented byformula (II), wherein:

wherein the chiral centers in formula (II) are S and R configurationsrespectively;

R₁ is one selected from a group consisting of a hydrogen, a hydroxylgroup and a methoxy group;

R₂ is one selected from a group consisting of a non-substituted phenylgroup, a mono-substituted phenyl group, a di-substituted phenyl group,or a tri-substituted phenyl, a pyridinyl and a C₄-C₆ cycloalkyl groups;R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is one selected from a group consisting of a hydroxyl group, a C1-C4alkoxyl group and a glycin-nitrile group.

In accordance with further another aspect of the present invention, adipeptide derivative is provided. The dipeptide derivative isrepresented by formula (II),

wherein:

the chiral centers in formula (II) are S and R configurationsrespectively; R₁ is selected from one of a hydrogen and a hydroxylgroup;

R₂ is one selected from a group consisting of non-substituted phenylgroup, mono-substituted phenyl group, di-substituted phenyl group, ortri-substituted phenyl group and pyridinyl group;

R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is selected from one of C1-C4 alkoxyl group and a glycin-nitrilegroup.

The above objects and advantages of the present invention will becomemore readily apparent to those ordinarily skilled in the art afterreviewing the following detailed descriptions and accompanying drawings,in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1( a)-1(b) show the influences of HCH6-1 on releasing lactatedehydrogenase from human neutrophils;

FIGS. 2( a)-2(u) show selective inhibition of HCH6-1 for fMLF-inducedCD11b expression in human neutrophils;

FIGS. 3( a)-3(h) show inhibition of HCH6-1 for the effect on FNLFNYKcombined with FPR1 on the membranes of human neutrophils; and

FIGS. 4( a)-4(d) show the significant capability of HCH6-1 to suppressphosphorylation for MAPKs (ERK, p38 and INK), as well as Akt.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing embodiments of this invention are presented herein for thepurposes of illustration and description only; they are not intended tobe exhaustive or to be limited to the precise form disclosed.

The excipient in the present invention also refers to a pharmaceuticallyacceptable carrier or excipient, or a bio-available carrier orexcipient, including a solvent, dispersant, coat, antibacterial orantifungal agent, preservative or slow absorber, which is a propercompound used to prepare a formulation in the prior art. Usually such acarrier or excipient does not have any activity for treatments itself.And the compound disclosed in the present invention cooperating with apharmaceutically acceptable carrier or excipient is prepared as variousformulations, and will not result in adverse drug reactions, allergiesor other inappropriate responses after being administered to animals orhumans. Thus the compound in the present invention, cooperating with apharmaceutically acceptable carrier or excipient, is for use in clinicsand human. “Effective dose” means a dose which is enough to improve orprevent medical symptoms or biological manifestation. Effective dose maybe also stated as casting dose for use in diagnosis. Unless there isother description in the specification, “active compound” and“pharmaceutically active compound” are substitutes for each other andrefer to a pharmaceutical, pharmacological or therapeutic substance aswell as other effective material.

A dipeptide derivative containing a formula (I) is disclosed in thepresent invention. The chiral centers in formula (I) are S and Rconfigurations respectively. RK and RT are respectively selected fromone of the combination of hydrogen atom, hydroxyl group, C₁-C₄ alkylgroup substitute on hydroxyl group, C₁-C₄ alkoxyl group, carboxylic acidgroup, C₁-C₄ alkyl nitrile substitute, C₁-C₄ alkyl substitute or C₁-C₄alkoxyl substitute on amide group, C₁-C₄ alkyl substitute on the estergroup or C₁-C₄ alkyl group substitute on the aromatic ring of benzoylgroup. RM and RS are respectively selected from hydrogen atom, hydroxylgroup, phenyl group, pyridinyl, carboxylic acid group, or C₁-C₄ alkoxylsubstitute on the ester group, or a hydroxyl group, halogen group, C₁-C₄alkoxyl group, C₁-C₄ alkyl group substitute on the aromatic ring ofbenzoyl group.

The dipeptide derivatives are synthesized via one of the followingSchemes 1-4. Compounds 2-13, 16-24, 25-27 and 14-15 are synthesized bySchemes 1-4 respectively. Each compound may be further classified intomajor or minor products and noted as ‘a’ or ‘b’ respectively. R₁-R₄ arerepresented as substitutions. A pharmaceutically acceptable salt,solvate or combination thereof may be adopted for the dipeptidederivatives.

Scheme 1 is for the preparation ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters and theiranalogs, with which compounds 2-13 are synthesized.

Reagents and conditions: (a) 2.0 N NaOH, aroyl chlorides, 20 h; (b)D-phenylalanine methyl ester, HBTU, DIEA, DCM, 6 h; (c) 2.0 N NaOH,benzoyl chloride, 20 h; and (d) D-phenylalaninol, HBTU, DIEA, DCM, 6 h.

Scheme 2 is for the preparation ofN—(N-nictotinoyl-L-trypto-phanyl)-D-phenylalanine methyl esters, withwhich compounds 16-24 are synthesized.

Reagents and conditions: (a) nicotinoyl chloride, pyridine, 20 h; (b)1.0 M LiOH, THF, 1 h; and (c) D-phenylalanine methyl ester, HBTU, DIEA,DCM, 6 h.

Scheme 3 is for the synthesis ofN—(N-benzoyl-L-tryptophanyl)-para-substituted-D-phenylalanine methylesters and N—(N-benzoyl-L-tryptophanyl)-3-cyclohexyl-D-alanine methylesters, with which compounds 25-27 are synthesized.

Reagents and conditions: (a) 20% TFA (TFA-DCM=1:4), 30 min; (b)MeOH-c-H2SO4, reflux, 2 h; and (c) N-benzoyl-L-tryptophan, HBTU, DIEA,DCM, 6 h.

Scheme 4 is for the preparation ofN—(N-benzoyl-L-tryptophanyl)-D-phenylalanine-glycine-nitriles, withwhich compounds 14-15 are synthesized.

Reagents and conditions: (a) aminoacetonitrile, HBTU, DIEA, DCM, 6 h;(b) 20% TFA (TFA-DCM=1:4), 30 min; and (c) N-benzoyl-L-tryptophan, HBTU,DIEA, DCM, 6 h.

Measurement of Elastase Release

Degranulation of azurophilic granules was determined by elastase releaseas described above. Experiments were performed usingMeO-Suc-Ala-Ala-Pro-Val-p-nitroanilide as the elastase substrate.Briefly, after supplementation withMeO-Suc-Ala-Ala-Pro-Val-p-nitroanilide (100 μM), neutrophils (6×10⁵ml⁻¹) were equilibrated at 37° C. for 2 min and incubated with drugs for5 min. Cells were activated by 30 nM fMLP or 1.5 nM WKYMVm for 10 minwith the pre-process of 0.5 μg ml⁻¹ CB for 3 min, and changes inabsorbance at 405 nm were continuously monitored to evaluate elastaserelease. Results are expressed as the percentage of elastase release inthe drug-free control group, DMSO.

Tables 1-6 demonstrate the inhibitory effects of dipeptide derivativesin the present invention on superoxide anion generation and elastaserelease by human neutrophils in response to specific activators of FPR1or FPR2.

Table 1 demonstrates the inhibitory effects ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters and theiranalogs on O₂ ^(•-) generation and elastase release by human neutrophilsin response to fMLP/CB.

TABLE 1 Anti-inflammation^(a) (μM) O₂ ^(•−) R₁ R₂ generation NE releaseEFB-1^(b)  0.16 ± 0.01 Sivelestat^(b) 0.046 ± 0.020  1  >20^(c)  1.70 ±0.60^(c)  3 H Phenyl  0.23 ± 0.02 0.60 ± 0.07 (HCH6-1)  4 H4-fluorophenyl >30 >30  5 H 4-chlorophenyl >30 10.40 ± 4.61   6 H4-methylphenyl  1.88 ± 0.29 2.47 ± 0.25  7 H 4-methoxyphenyl >30 >30  8H Benzyl 10.17 ± 4.53 5.71 ± 0.39  9 H Benzylmethyl 10.10 ± 3.05 12.54 ±4.87  10 H Benzyloxyl 17.43 ± 1.85 8.92 ± 4.84 11a OH Phenyl  8.81 ±1.22 9.11 ± 0.76 11b OH Phenyl 18.67 ± 4.02 22.11 ± 4.96  15a HPyridinyl 13.11 ± 0.50 >30 15b H Pyridinyl >30 >30 (note) ^(a)The IC₅₀values are presented as mean ± SEM. (n = 3). ^(b)Sivelestat and EFB-1were used as positive controls in the present invention. ^(c)Thebiological data were from the literature directly.

Table 2 demonstrates the inhibitory effects ofN—(N-benzoyl-L-tryptophanyl)-para-substituted-D-phenylalanine methylesters and N—(N-benzoyl-L-tryptophanyl)-3-cyclohexyl-Dalanine methylesters on O₂ ^(•-) generation and elastase release by human neutrophilsin response to fMLP/CB.

TABLE 2 Anti-inflammation^(a) (μM) O₂ ^(•−) R₃ generation NE releaseEFB-1^(b) 0.16 ± 0.01 Sivelestat^(b) 0.046 ± 0.020  3(HCH6-1) benzyl0.23 ± 0.02 0.60 ± 0.07 18a 4-nitrobenzyl 18.99 ± 2.70  11.17 ± 0.46 18b 13.08 ± 0.40  15.39 ± 0.54  19a 4-methylbenzyl 1.87 ± 0.22 3.60 ±0.05 19b 18.83 ± 5.80  23.99 ± 2.02  20a 4-fluorobenzyl 5.40 ± 1.5011.49 ± 2.20  20b 14.01 ± 1.21  19.37 ± 0.71  21a 4-chlorobenzyl 4.41 ±0.27 4.31 ± 0.52 21b 5.26 ± 0.84 12.41 ± 3.53  22a 4-bromobenzyl 6.82 ±3.09 2.41 ± 1.60 22b 15.97 ± 0.83  7.20 ± 3.36 23a 4-trifluoro- 17.25 ±1.94  21.05 ± 2.92  23b methylbenzyl 3.16 ± 0.52 8.76 ± 2.33 24acyclohexylmethyl 0.12 ± 0.02 0.37 ± 0.04 24b 1.32 ± 0.14 1.03 ± 0.02(note) ^(a)The IC₅₀ values are presented as mean ± SEM (n = 3).^(b)Sivelestat and EFB-1 were used as positive controls in the presentinvention.

Table 3 demonstrates the inhibitory effects ofN—(N-benzoyl-L-tryptophanyl)-D-phenylalanine analogs/derivatives on O₂^(•-) generation and elastase release by human neutrophils in responseto fMLP/CB.

TABLE 3 Anti-inflammation^(a) (μM) O₂ ^(•−) R₁ R₄ generation NE releaseEFB-1^(b) 0.16 ± 0.01 Sivelestat^(b) 0.046 ± 0.020  3(HCH6-1) H COOCH₃0.23 ± 0.02 0.60 ± 0.07 27a H CONHCH₂CN 4.23 ± 2.44 4.69 ± 0.80 27b HCONHCH₂CN 10.51 ± 4.23  14.51 ± 2.87  12a OH CH₂OH >30 >30 12b OHCH₂OH >30 >30 13a H CH₂OH >30 >30 13b H CH₂OH >30 >30 (note) ^(a)TheIC₅₀ values are presented as mean ± SEM (n = 3). ^(b)Sivelestat andEFB-1 were used as positive controls in the present invention.

Table 4 demonstrates respectively inhibitory the effects of compounds 3,6, 24a, and 24b on O₂ ^(•-) generation and elastase release by humanneutrophils in response to fMLP/CB and WKYMVm/CB.

TABLE 4 fMLF/CB WKYMVm/CB (μM)^(a) (μM)^(a) O₂ ^(•−) O₂ ^(•−) compoundsgeneration NE release generation NE release CycH^(b) 0.04 ± 0.01 0.04 ±0.01 2.02 ± 0.18 0.17 ± 0.01 WRW4^(b) 2.26 ± 0.48 1.14 ± 0.27 0.38 ±0.01 0.59 ± 0.09  3(HCH6-1) 0.23 ± 0.02 0.60 ± 0.07 4.83 ± 0.66 4.61 ±0.72  6 1.88 ± 0.29 2.47 ± 0.25 6.55 ± 0.59 1.96 ± 0.11 24a 0.12 ± 0.020.37 ± 0.04 1.58 ± 0.04 1.62 ± 0.04 24b 1.32 ± 0.14 1.03 ± 0.02 4.27 ±0.31 1.06 ± 0.05 (note) ^(a)The IC₅₀ values are presented as mean ± SEM(n = 3). ^(b)Cyclosporin H (CycH) and WRW4 were used as positivecontrols.

Tables 5 and 6 explore whether there is an anti-inflamatory effect inthe dipeptide derivatives. Because ferricytochrome c cannot penetratecell membranes, it reacts with superoxide anion extracellularly. Also,there are absorptive reactions at 550 nm, and differences among theabsorptive reactions can be used to evaluate the influence on therelease of superoxide anion. The elastase is released by degranulationas the neutrophil is activated. Tables 5 and 6 use the substrate,MeO-Suc-Ala-Ala-Pro-Val-p-nitroanilide, with the specificity forreacting with the elastase so as to evaluate the influence of thecandidate compound on the elastase release.

Table 5 demonstrates the comparison for each of compound 3 (HCH6-1),compound 6 (HCH30-2), compound 19a (HCH108-4), compound 19b (HCH108-3),compound 22a (HCH113-4), compound 22b (HCH113-3), compound 24a(HCH99-2), compound 24b (HCH99-1), compound 27a (HCH90-2-2) and compound27b (HCH90-2-1) inhibiting superoxide anion generation of humanneutrophils induced by specific activator of FPR1, fMLP and specificactivator of FPR2, WKYMVm. The IC₅₀ values in Tables 5-6 are presentedas mean±SEM (n=4 or 8), ***p<0.001 (compared to the control), and Inh %is the inhibitory percentage under 10 μM.

TABLE 5 Superoxide anion fMLF WKYMVm Compound IC₅₀ (μM)^(a) Inh % IC₅₀(μM)^(a) Inh % HCH 30-2 1.88 ± 0.29 — 6.55 ± 0.59 — HCH 90-2-1 — 34.61 ±— 18.66 ± 0.7 *** 4.1 *** HCH 90-2-2 6.23 ± 1.05 — — 28.79 ± 2.6 *** HCH99-1 1.32 ± 0.14 — 4.27 ± 0.31 — HCH 99-2 0.19 ± 0.07 — 1.58 ± 0.04 —HCH 108-3 1.87 ± 0.22 — — 31.00 ± 2.7 *** HCH 108-4 4.88 ± 0.18 — 4.06 ±0.77 — HCH 113-3 1.41 ± 0.26 — 5.39 ± 0.45 — HCH 113-4 0.83 ± 0.05 —2.14 ± 0.36 — HCH 6-1 0.32 ± 0.03 — 4.98 ± 0.27 —

Table 6 demonstrates the comparison for each of compound 3 (HCH6-1),compound 6 (HCH30-2), compound 19a (HCH108-4), compound 19b (HCH108-3),compound 22a (HCH113-4), compound 22b (HCH113-3), compound 24a(HCH99-2), compound 24b (HCH99-1), compound 27a (HCH90-2-2) and compound27b (HCH90-2-1) inhibiting elastase release of human neutrophils inducedby specific activator of FPR1, fMLP and specific activator of FPR2,WKYMVm. The IC₅₀ values in Tables 5-6 are presented as mean±SEM (n=4 or8), ***p<0.001 (compared to the control), and Inh % is the inhibitorypercentage under 10 μM.

TABLE 6 Elastase release fMLF WKYMVm Compound IC₅₀ (μM)^(a) Inh % IC₅₀(μM)^(a) Inh % HCH 30-2 2.47 ± 0.25 — 1.96 ± 0.11 — HCH 90-2-1 — 18.66 ±0.7 *** 6.65 ± 0.23 — HCH 90-2-2 — 28.79 ± 2.6 *** — 35.9 ± 0.8 *** HCH99-1 1.03 ± 0.02 — 1.06 ± 0.05 — HCH 99-2 0.37 ± 0.04 — 1.62 ± 0.04 —HCH 108-3 3.60 ± 0.05 31.00 ± 2.7 *** 2.07 ± 0.21 — HCH 108-4 1.24 ±0.04 — 6.04 ± 0.47 — HCH 113-3 1.87 ± 0.03 — 7.31 ± 0.63 — HCH 113-40.89 ± 0.06 — 3.15 ± 0.32 — HCH 6-1 0.57 ± 0.07 — 5.22 ± 0.70 —

Please refer to Tables 5-6. By fMLF (FPR1 activator) triggeringneutrophils, it can be seen that a series of dipeptide derivatives iscapable of inhibiting superoxide anion and elastase, which are releasedby human neutrophils. WKYMVm (FPR1/2 activator) is utilized to stimulatethe cells, and then the inhibitory effect becomes weak. It is found thatthese dipeptide derivatives selectively inhibit activated neutrophilsinduced by fMLP. From tables 5 and 6, it can be found that HCH99-2(compound 24a) and HCH6-1 (compound 3) expressed excellent inhibitoryeffect with IC₅₀ being 0.19±0.07 μM and 0.32±0.03 μM respectively. Forthe selectivity for FPR1/2 and FPR1, the differences became 8 fold forcompound 24a and 15 fold for compound 3.

Embodiments 1-5 are preparing methods for the dipeptide derivatives inthe present invention.

Embodiment 1 General Procedure for the Synthesis ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine methyl esters (compounds 3-7)and their analogs (compounds 8-10, 11a and 11 b)

To a mixture solution of L-tryptophan (2a, 1.0 equiv.) or5-hydroxy-L-tryptophan (2b, 1.0 equiv.) in 2 N NaOH aqueous solution wasadded suitable acyl chlorides (1.1 equiv.), respectively. The reactionmixture was stirred at room temperature for 3.0 h, and then 1 N HClsolution was added and the pH values were adjusted to 1-2. The mixturesolution was further partitioned by chloroform, and the organic layerwas evaporated at reduced pressure to yield intermediates. Theintermediates and D-phenylalanine methyl ester (1.0 mmole) weredissolved in DCM, and then HBTU (2.0 equiv.) and DIEA (1.5 equiv.) wereadded. The reaction mixture was stirred for 6 hours at room temperature,concentrated, and purified by silica gel column chromatography using amixture of n-hexane-ethyl acetate (6:4) or n-hexane-acetone (7:3),respectively, to afford products (compounds 3-10, 11a and 11b).

Compound 3, also known as HCH6-1N—(N-Benzoyl-L-tryptophanyl)-D-phenylalanine methyl ester

52% yield. White powder, mp 174-176° C. CD (c 0.11 mM, MeOH) nm (mdeg)261 (−0.43), 253 (−0.40), 239 (−0.01), 223 (0.46) nm. ¹H NMR (C₅D₅N) δ11.79 (1H, s, NH), 9.41 (1H, d, J=8.0 Hz, CONH), 9.06 (1H, d, J=8.0 Hz,NH), 8.06 (2H, d, J=7.2 Hz), 7.88 (1H, d, J=8.0 Hz), 7.54 (1H, d, J=8.0Hz), 7.36-7.12 (11H, m), 5.67 (1H, ddd, J=14.4, 7.2, 7.2 Hz), 5.23 (1H,ddd, J=14.0, 7.2, 7.2 Hz), 3.77 (1H, dd, J=14.6, 7.2 Hz), 3.63 (1H, dd,J=14.4, 6.8 Hz), 3.50 (3H, s), 3.20 (1H, dd, J=13.6, 7.2 Hz), 3.09 (1H,dd, J=13.6, 7.2 Hz). 13C NMR (C5D5N) δ 172.9 (s), 172.5 (s), 168.0 (s),137.7 (3×C, s), 131.6 (d), 130.0 (2×C, d), 129.0 (2×C, d), 128.9 (s),128.7 (2×C, d), 128.2 (2×C, d), 127.3 (d), 124.6 (d), 122.0 (d), 119.5(2×C, d), 112.2 (d), 111.4 (s), 55.5 (d), 54.6 (d), 52.0 (q), 38.2 (t),29.20 (t). ESI-MS (m/z, %): 492 [M+Na]⁺ (100), 470 [M+1]⁺ (44).HR-ESI-MS m/z 492.1901 [M+Na]⁺ (calcd for C₂₈H₂₇N₃O₄Na 492.1899).

Compound 4 N—(N-4-Fluorobenzoyl-L-tryptophanyl)-D-phenylalanine methylester

31% yield. White powder, mp 191-193° C. ¹H NMR (C₅D₅N) δ 11.81 (1H, s),9.48 (1H, d, J=8.0 Hz), 9.11 (1H, d, J=8.0 Hz), 8.04 (2H, dd, J=8.0 Hz),7.87 (1H, d, J=7.6 Hz), 7.52 (1H, d J=8.0 Hz, H-7), 7.32 (1H, s),7.26-7.13 (7H, m), 7.02 (2H, t, J=8.6 Hz), 5.66 (1H, ddd, J=14.6, 7.2,7.2 Hz), 5.24 (1H, ddd, J=14.2, 7.2, 7.2 Hz), 3.75 (1H, dd, J=14.4, 6.8Hz), 3.61 (1H, dd, J=14.4, 6.8 Hz), 3.51 (3H, s), 3.20 (1H, dd, J=14.2,7.2 Hz), 3.09 (1H, dd, J=14.2, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 174.4 (s),174.0 (s), 168.4 (s), 166.4 (s, J_(C-F)=248.0 Hz), 139.2 (2×C, s), 133.5(s), 132.2 (2×C, d, J_(C-F)=9.0 Hz), 131.5 (2×C, d), 130.5 (2×C, d),130.4 (s), 128.8 (d), 126.1 (d), 123.5 (d), 121.0 (2×C, d), 117.0 (2×C,d, J_(C-F)=22.0 Hz), 113.7 (d), 112.9 (s), 57.1 (d), 56.1 (d), 53.6 (q),39.7 (t), 30.7 (t). ESI-MS (m/z, %): 510 [M+Na]⁺ (100), 488 [M+1]⁺ (37).HRESI-MS m/z 510.1802 [M+Na]⁺ (calcd for C₂₈H₂₆FN₃O₄Na 510.1805).

Compound 5 N—(N-4-Chlorobenzoyl-L-tryptophanyl)-D-phenylalanine methylester

23% yield. White powder, mp 191-193° C. ¹H NMR (C₅D₅N) δ 11.82 (1H, s),9.48 (1H, d, J=7.6 Hz), 9.18 (1H, d, J=8.0 Hz), 7.96 (2H, d, J=8.4),7.85 (1H, d, J=8.0 Hz), 7.51 (1H, d, J=8.0 Hz), 7.28 (1H, s), 7.26-7.12(9H, m), 5.65 (1H, ddd, J=14.6, 6.8, 6.8 Hz), 5.24 (1H, ddd, J=14.0,7.6, 7.6 Hz), 3.74 (1H, dd, J=14.4, 6.8 Hz), 3.59 (1H, dd, J=14.2, 7.2Hz), 3.50 (3H, s), 3.20 (1H, dd, J=13.8, 7.6 Hz), 3.08 (1H, dd, J=13.6,7.6 Hz). ¹³C NMR (C₅D₅N) δ 172.8 (s), 172.5 (s), 166.9 (s), 137.7 (s),137.3 (s), 135.7 (s), 134.2 (s), 130.0 (2×C, d), 129.9 (2×C, d), 129.0(2×C, d), 128.9 (s), 128.8 (2×C, d), 127.3 (d), 124.5 (d), 122.0 (d),119.5 (2×C, d), 112.2 (d), 111.3 (s), 55.6 (d), 54.6 (d), 52.0 (q), 38.2(t), 29.1 (t). ESI-MS (m/z, %): 526 [M+Na]⁺ (100), 504 [M+1]⁺ (33).HR-ESI-MS m/z 526.1506 [M+Na]⁺ (calcd for C₂₈H₂₆ClN₃O₄Na 526.1509).

Compound 6 N—(N-4-Methylbenzoyl-L-tryptophanyl)-D-phenylalanine methylester

39% yield. White powder, mp 169-171° C. ¹H NMR (C₅D₅N) δ 11.77 (1H, s),9.41 (1H, d, J=8.0 Hz), 8.98 (1H, d, J=8.0 Hz), 8.00 (2H, d, J=8.0 Hz),7.89 (1H, d, J=7.6 Hz), 7.54 (1H, d, J=8.4 Hz), 7.33 (1H, s), 7.30-7.14(7H, m), 7.05 (2H, d, J=7.6 Hz), 5.69 (1H, ddd, J=14.4, 6.8, 6.8 Hz),5.23 (1H, ddd, J=14.0, 7.2, 7.2 Hz), 3.79 (1H, dd, J=14.6, 6.8 Hz), 3.65(1H, dd, J=14.4, 6.8 Hz), 3.51 (3H, s), 3.21 (1H, dd, J=13.8, 6.8 Hz),3.09 (1H, dd, J=13.6, 7.2 Hz), 2.13 (3H, s). ¹³C NMR (C₅D₅N) δ 174.5(s), 174.0 (s), 169.5 (s), 143.4 (s), 139.2 (2×C, s), 134.3 (s), 131.5(2×C, d), 130.9 (2×C, d), 130.5 (2×C, d), 130.4 (s), 129.8 (2×C, d),128.8 (d), 126.1 (d), 123.5 (d), 121.0 (2×C, d), 113.7 (d), 112.9 (s),57.0 (d), 56.2 (d), 53.6 (q), 39.7 (t), 30.7 (t), 22.9 (q). ESI-MS (m/z,%): 506 [M+Na]⁺ (99), 484 [M+1]⁺ (100). HR-ESI-MS m/z 506.2059 [M+Na]⁺(calcd for C₂₉H₂₉N₃O₄Na 506.2056).

Compound 7 N—(N-4-Methoxylbenzoyl-L-tryptophanyl)-D-phenylalanine methylester

47% yield. White powder, mp 151-153° C. ¹H NMR (C₅D₅N) δ 11.80 (1H, s),9.39 (1H, d, J=8.0 Hz), 8.92 (1H, d, J=8.0 Hz), 8.09 (2H, d, J=8.4 Hz),7.99 (1H, d, J=8.0 Hz), 7.53 (1H, d, J=8.0 Hz), 7.33 (1H, s), 7.33-7.13(7H, m), 6.88 (2H, d, J=8.4 Hz), 5.69 (1H, ddd, J=14.4, 6.8, 6.8 Hz),5.23 (1H, ddd, J=14.0, 7.2, 7.2 Hz), 3.78 (1H, dd, J=14.2, 6.8 Hz), 3.64(1H, dd, J=14.6, 6.8 Hz), 3.59 (3H, s), 3.50 (3H, s), 3.20 (1H, dd,J=13.6, 7.2 Hz), 3.09 (1H, dd, J=13.6, 7.6 Hz). ¹³C NMR (C₅D₅N) δ 174.6(s), 174.0 (s), 169.0 (s), 164.1 (s), 139.2 (2×C, s), 131.6 (2×C, d),131.5 (2×C, d), 130.5 (2×C, d), 130.4 (s), 129.4 (s), 128.8 (d), 126.1(d), 123.5 (d), 121.0 (2×C, d), 115.6 (2×C, d), 113.7 (d), 113.0 (s),57.0 (q), 56.9 (d), 56.1 (d), 53.6 (q), 39.03 (t), 30.7 (t). ESI-MS(m/z, %): 522 [M+Na]⁺ (100), 500 [M+1]⁺ (38). HR-ESI-MS m/z 522.2007[M+Na]⁺ (calcd for C₂₉H₂₉N₃O₅Na 522.2005).

Compound 8 N—(N-Phenylacetyl-L-tryptophanyl)-D-phenylalanine methylester

43% yield. White powder, mp 182-184° C. ¹H NMR (C₅D₅N) δ 11.76 (1H, s),9.34 (1H, d, J=8.0 Hz), 8.98 (1H, d, J=8.4 Hz), 7.81 (1H, d, J=8.0 Hz),7.53 (1H, d, J=8.4 Hz), 7.33 (2H, d, J=7.2 Hz), 7.27-7.13 (11H, m), 5.50(1H, ddd, J=14.6, 6.8, 6.8 Hz), 5.19 (1H, ddd, J=14.0, 7.2, 7.2 Hz),3.75-3.46 (4H, m), 3.49 (3H, s), 3.17 (1H, dd, J=13.6, 6.8 Hz), 3.05(1H, dd, J=13.8, 6.8 Hz). ¹³C NMR (C₅D₅N) δ 172.8 (s), 172.5 (s), 171.1(s), 137.7 (s), 137.6 (s), 136.9 (s), 130.0 (2×C, d), 129.9 (2×C, d),129.0 (2×C, d), 128.9 (s), 128.9 (2×C, d), 127.3 (d), 127.0 (d), 124.5(d), 121.9 (d), 119.5 (d), 119.4 (d), 112.1 (d), 111.2 (s), 54.9 (d),54.6 (d), 52.0 (q), 43.5 (t), 38.2 (t), 29.3 (t). ESI-MS (m/z, %): 506[M+Na]⁺ (100), 484 [M+1]⁺ (87). HR-ESI-MS m/z 506.2060 [M+Na]⁺ (calcdfor C₂₉H₂₉N₃O₄Na 506.2056).

Compound 9 N—(N-Phenylpropanoyl-L-tryptophanyl)-D-phenylalanine methylester

24% yield. White powder, mp 159-161° C. ¹H NMR (C₅D₅N) δ 11.78 (1H, s),9.27 (1H, d, J=8.0 Hz), 8.88 (1H, d, J=8.4 Hz), 7.85 (1H, d, J=7.6 Hz),7.55 (1H, d, J=7.6 Hz), 7.27-7.12 (13H, m), 5.52 (1H, ddd, J=14.8, 7.2,7.2 Hz), 5.21 (1H, ddd, J=14.0, 7.2, 7.2 Hz), 3.65 (1H, dd. J=14.4, 6.8Hz), 3.50 (3H, s), 3.50-3.45 (1H, m), 3.17 (1H, J=13.6, 6.8 Hz),3.09-2.97 (3H, m), 2.67-2.61 (2H, m). ¹³C NMR (C₅D₅N) δ 174.4 (s), 174.0(s), 173.9 (s), 143.7 (s), 139.2 (2×C, s), 131.5 (2×C, d), 130.5 (2×C,d), 130.4 (d), 130.4 (d), 130.3 (2×C, d), 128.8 (s), 128.0 (d), 126.0(d), 123.4 (d), 121.0 (d), 120.9 (d), 113.6 (d), 112.9 (s), 56.4 (d),56.0 (d), 53.5 (q), 39.7 (2×C, t), 33.7 (t), 30.8 (t). ESI-MS (m/z, %):520 [M+Na]⁺ (100), 498 [M+1]⁺ (39). HR-ESI-MS m/z 520.2215 [M+Na]⁺(calcd for C₂₉H₂₉N₃O₄Na 520.2212).

Compound 10 N—(N-Benzyloxycarbonyl-L-tryptophanyl)-D-phenylalaninemethyl ester

67% yield. White powder, mp 147-149° C. ¹H NMR (C₅D₅N) δ 11.76 (1H, s),9.32 (1H, d, J=7.6 Hz), 8.63 (1H, d, J=8.4 Hz), 7.88 (1H, d, J=7.6 Hz),7.54 (1H, d, J=8.4 Hz), 7.32-7.14 (13H, m), 5.25-5.13 (4H, m), 3.72 (1H,dd, J=14.4, 7.2 Hz), 3.55 (1H, dd, J=14.8, 7.2 Hz), 3.49 (3H, s), 3.17(1H, dd, J=13.6, 7.2 Hz), 3.07 (1H, dd, J=13.8, 7.2 Hz). 13C NMR (C5D5N)δ 172.9 (s), 172.5 (s), 157.2 (s), 137.9 (s), 137.7 (2×C, s), 130.0(2×C, d), 129.0 (2×C, d), 129.0 (d), 128.9 (2×C, d), 128.9 (s), 128.3(2×C, d), 127.3 (s), 124.6 (d), 122.0 (d), 119.5 (2×C, d), 112.2 (d),111.3 (s), 66.6 (t), 57.0 (d), 54.5 (d), 52.0 (q), 38.2 (t), 29.7 (t).ESI-MS (m/z, %): 522 [M+Na]⁺ (100), 500 [M+1]⁺ (30). HR-ESI-MS m/z522.2008 [M+Na]⁺ (calcd for C₂₉H₂₉N₃O₅Na 522.2005).

N—(N-Benzoyl-5-hydroxy-L-tryptophanyl)-D-phenylalanine methyl esters(compounds 11a and 11b) Compound 11a

23% yield. White powder, mp 112-114° C. ¹H NMR (CDCl₃) δ 11.54 (1H, s,NH), 9.39 (1H, d, J=8.0 Hz, NH), 9.04 (1H, d, J=8.0 Hz, NH), 8.06 (2H,d, J=7.2 Hz), 7.74 (1H, d, J=2.0 Hz), 7.47 (1H, d, J=8.8 Hz), 7.35 (1H,t, J=7.2 Hz), 7.29-7.13 (9H, m), 5.65 (1H, dd, J=14.2, 7.2 Hz), 5.23(1H, dd, J=14.2, 7.2 Hz), 3.72 (1H, dd, J=14.2, 7.2 Hz), 3.59 (1H, dd,J=14.2, 7.2 Hz), 3.47 (3H, s), 3.15 (1H, dd, J=13.6, 7.2 Hz), 3.05 (1H,dd, J=13.6, 7.2 Hz). ¹³C NMR (CDCl₃) δ 172.7 (s), 172.3 (s), 167.7 (s),152.4 (s), 137.4 (s), 135.5 (s), 132.2 (s), 131.4 (d), 129.8 (s), 129.8(2×C, d), 128.8 (2×C, d), 128.5 (2×C, d), 128.0 (2×C, d), 127.1 (d),125.0 (d), 112.8 (d), 112.6 (d), 110.3 (s), 103.9 (d), 55.5 (d), 54.5(d), 51.8 (q), 38.0 (t), 29.2 (t). ESI-MS (m/z, %): 508 [M+Na]⁺ (100).HR-ESI-MS m/z 508.1850 [M+Na]⁺ (calcd for C₂₈H₂₇N₃O₅Na 508.1848).

Compound 11b

17% yield. White powder, mp 110-112° C. ¹H NMR (CDCl₃) δ 11.53 (1H, s,NH), 9.41 (1H, d, J=8.0 Hz, NH), 9.11 (1H, d, J=8.0 Hz, NH), 8.10 (2H,d, J=8.0 Hz), 7.64 (1H, d, J=1.6 Hz), 7.43 (1H, d, J=8.0 Hz), 7.37 (1H,t, J=7.6 Hz), 7.30 (2H, t, J=7.6 Hz), 7.26 (2H, t, J=7.6 Hz), 7.19-7.13(4H, m), 7.08 (1H, t, J=8.0 Hz), 5.65 (1H, dd, J=14.4, 7.2 Hz), 5.21(1H, dd, J=14.2, 7.2 Hz), 3.74 (1H, dd, J=14.4, 7.2 Hz), 3.61 (1H, dd,J=14.4, 7.2 Hz), 3.55 (3H, s), 3.27 (1H, dd, J=13.6, 7.2 Hz), 3.15 (1H,dd, J=13.6, 7.2 Hz). ¹³C NMR (CDCl₃) δ 172.6 (s), 172.3 (s), 167.8 (s),152.3 (s), 137.5 (s), 135.5 (s), 132.2 (s), 131.4 (d), 129.8 (2×C, d),129.7 (s), 128.7 (2×C, d), 128.6 (2×C, d), 128.1 (2×C, d), 127.0 (d),125.0 (d), 112.8 (d), 112.5 (d), 110.3 (s), 103.9 (d), 55.2 (d), 54.5(d), 51.9 (q), 38.2 (t), 28.9 (t). ESI-MS (m/z, %): 508 [M+Na]⁺ (100).HR-ESI-MS m/z 508.1851 [M+Na]⁺ (calcd for C₂₈H₂₇H₃O₅Na 508.1848).

Embodiment 2 General procedure for the synthesis ofN—(N-benzoyl-L-tryptophanyl)-D-phenylalaninol derivatives (compounds12a-13a and 12b-13b)

N-Benzoyl-L-tryptophan and N-benzoyl-5-hydroxy-L-tryptophan wereobtained by a similar procedure as described above. DissolveN-benzoyl-L-tryptophan (1.0 equiv.) or N-benzoyl-5-hydroxy-L-tryptophan(1.0 equiv.) in DCM respectively, and then D-phenylalaninol (1.0equiv.), HBTU (2.0 equiv.) and DIEA (1.5 equiv.) were added. Thereaction mixture was stirred at room temperature for 6.0 h, and purifiedby silica gel column chromatography using ethyl acetate or MeOH—CHC13(1:20) to afford the mixtures 12a/b and 13a/b. The mixture was furtherpurified by HPLC (mobile phase: 35% acetonitrile+0.3% TFA) to affordproducts.

N—(N-Benzoyl-L-tryptophanyl)-5-hydroxy-D-phenylalaninol (compounds 12aand 12b) Compound 12a

16% yield. White powder, mp 175-177° C. ¹H NMR (C₅D₅N) δ 11.77 (1H, s,NH), 8.97 (1H, d, J=8.0 Hz, NH), 8.88 (1H, d, J=8.0 Hz, NH), 8.05 (2H,d, J=7.2 Hz), 7.89 (1H, d, J=8.0 Hz), 7.51 (1H, d, J=8.0 Hz), 7.36-7.32(4H, m), 7.28-7.22 (5H, m), 7.19 (1H, m), 7.09 (1H, t, J=7.6 Hz), 5.58(1H, dd, J=14.4, 6.8 Hz), 5.50 (1H, br.s, OH), 4.75 (1H, m), 3.91 (2H,m), 3.75 (1H, dd, J=14.4, 6.8 Hz), 3.64 (1H, dd, J=14.4, 6.8 Hz), 3.15(1H, dd, J=13.4, 7.2 Hz), 3.03 (1H, dd, J=13.4, 7.2 Hz). ¹³C NMR (C₅D₅N)δ 172.7 (s), 167.9 (s), 139.8 (s), 137.7 (s), 135.7 (s), 131.5 (d),130.2 (d), 129.0 (s), 128.9 (2×C, d), 128.7 (2×C, d), 128.2 (2×C, d),126.7 (d), 124.6 (d), 121.9 (d), 119.5 (d), 119.4 (d), 112.1 (d), 111.5(s), 63.2 (t), 55.9 (d), 53.8 (d), 37.7 (t), 29.4 (t). ESI-MS (m/z, %):464 [M+Na]⁺ (100), 442 [M+1]⁺ (5). HR-ESI-MS m/z 464.1947 [M+Na]⁺ (calcdfor C₂₇H₂₇N₃O₃Na 464.1950).

Compound 12b

11% yield. White powder, mp 173-175° C. ¹H NMR (C₅D₅N) δ 11.78 (1H, s,NH), 9.07 (1H, d, J=7.6 Hz, NH), 8.87 (1H, d, J=8.0 Hz, NH), 8.09 (2H,d, J=7.6 Hz), 7.85 (1H, d, J=8.0 Hz), 7.52 (1H, br.s), 7.48 (1H, d,J=8.0 Hz), 7.29 (2H, t, J=7.6 Hz), 7.27 (2H, t, J=7.6 Hz), 7.22-7.15(3H, m), 7.09 (2H, t, J=8.6 Hz), 5.62 (1H, dd, J=14.4, 7.2 Hz), 4.71(1H, m), 3.87 (2H, m), 3.80 (1H, dd, J=14.4, 7.2 Hz), 3.68 (1H, dd,J=14.4, 7.2 Hz), 3.21 (1H, dd, J=13.6, 6.8 Hz), 3.09 (1H, dd, J=13.6,6.8 Hz). ¹³C NMR (C₅D₅N) δ 172.5 (s), 167.8 (s), 139.6 (s), 137.5 (s),135.5 (s), 131.4 (d), 129.9 (2×C, d), 128.7 (s), 128.6 (2×C, d), 128.5(2×C, d), 128.1 (2×C, d), 126.4 (d), 124.4 (d), 121.7 (d), 119.3 (d),119.2 (d), 111.9 (d), 111.4 (s), 63.1 (t), 55.5 (d), 53.8 (d), 37.6 (t),28.8 (t). ESI-MS (m/z, %): 464 [M+Na]⁺ (100), 442 [M+1]⁺ (37). HR-ESI-MSm/z 464.1947 [M+Na]⁺ (calcd for C₂H₂₇N₃O₃Na 464.1950).

N—(N-Benzoyl-L-tryptophanyl)-D-phenylalaninol (compounds 13a and 13b)Compound 13a

53% yield. White powder, mp 151-153° C. ¹H NMR (C₅D₅N) δ 11.53 (1H, s,NH), 8.96 (1H, d, J=7.6 Hz, NH), 8.82 (1H, d, J=8.0 Hz, NH), 8.07 (2H,d, J=7.6 Hz), 7.76 (1H, s), 7.46 (1H, d, J=8.4 Hz), 7.34-7.13 (10H, m),5.95 (1H, br.s, OH), 5.56 (1H, dd, J=14.0, 7.2 Hz), 4.73 (1H, m), 3.91(1H, dd, J=10.8, 5.2 Hz), 3.85 (1H, dd, J=10.8, 5.2 Hz), 3.70 (1H, dd,J=14.0, 7.2 Hz), 3.60 (1H, dd, J=14.0, 7.2 Hz), 3.11 (1H, dd, J=13.6,7.2 Hz), 3.00 (1H, dd, J=13.6, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 172.5 (s),167.6 (s), 152.4 (s), 139.5 (s), 135.5 (s), 132.2 (s), 131.4 (d), 130.1(2×C, d), 129.8 (s), 128.7 (2×C, d), 128.5 (2×C, d), 128.0 (2×C, d),125.0 (d), 112.8 (d), 112.5 (d), 110.5 (s), 104.0 (d), 62.8 (t), 55.8(d), 53.6 (d), 37.5 (t), 29.5 (t). ESI-MS (m/z, %): 480 [M+Na]⁺ (100),458 [M+1]⁺ (18). HR-ESI-MS m/z 480.1897 [M+Na]⁺ (calcd for C₂₇H₂₇N₃O₄Na480.1899).

Compound 13b

25% yield. White powder, mp 120-122° C. ¹H NMR (C₅D₅N) δ 11.53 (1H, s,NH), 9.05 (1H, d, J=8.0 Hz, NH), 8.76 (1H, d, J=8.0 Hz, NH), 8.10 (2H,d, J=7.6 Hz), 7.71 (1H, s), 7.55 (1H, s), 7.46 (1H, d, J=8.0 Hz),7.38-7.35 (3H, m), 7.30 (2H, t, J=7.6 Hz), 7.18-7.14 (4H, m), 7.08 (1H,d, J=8.0 Hz), 5.90 (1H, br.s, OH), 5.59 (1H, dd, J=14.2, 7.2 Hz), 4.69(1H, m), 3.88 (1H, dd, J=10.4, 5.2 Hz), 3.82 (1H, dd, J=10.4, 5.2 Hz),3.74 (1H, dd, J=14.2, 7.2 Hz), 3.64 (1H, dd, J=14.2, 7.2 Hz), 3.20 (1H,dd, J=13.6, 7.2 Hz), 3.07 (1H, dd, J=13.6, 7.2 Hz). ¹³C NMR (C₅D₅N) δ172.4 (s), 167.7 (s), 152.3 (s), 139.6 (s), 135.5 (s), 132.2 (s), 131.4(d), 129.9 (2×C, d), 129.8 (s), 128.6 (2×C, d), 128.5 (2×C, d), 128.1(2×C, d), 126.4 (d), 125.0 (d), 112.8 (d), 112.5 (d), 110.6 (s), 104.0(d), 63.8 (t), 55.5 (d), 53.7 (d), 37.6 (t), 28.9 (t). ESI-MS (m/z, %):480 [M+Na]⁺ (100), 458 [M+1]⁺ (82). HR-ESI-MS m/z 480.1897 [M+Na]⁺(calcd for C₂₇H₂₇N₃O₄Na 480.1899).

Embodiment 3 Preparation ofN—(N-nicotinoyl-L-tryptophanyl)-D-phenylalanine methyl esters (compounds15a and 15b)

A mixture solution of L-tryptophan methyl ester (1.0 equiv.) in pyridineand nicotinoyl chlorides (1.1 equiv.) was prepared. The reaction mixturewas stirred at room temperature for 16.0 h, and then evaporated andpurified by silica gel column chromatography using a mixture ofMeOH—CHCl₃ (1:20) to afford N-nicotinoyl-L-tryptophan methyl ester.N-Nicotinoyl-L-tryptophan methyl ester was further dissolved in 10 mL of1.0 M LiOH solution, and then added to the mixture for hydrolysis. Uponcompletion, the reaction mixture was partitioned for three times withethyl acetate and saturated sodium bicarbonate aqueous solution. Thecombined aqueous layer was neutralized with 1.0 N HCl solution, followedby extraction with ethyl acetate for three times. The combined organiclayer was dried with anhydrous magnesium sulfate and evaporated to yieldN-nicotinoyl-L-tryptophan. D-Phenylalanine methyl ester (1.0 mmole) andN-nicotinoyl-L-tryptophan were dissolved in DCM, and then HBTU (2.0equiv.) and DIEA (1.5 equiv.) were added. The reaction mixture wasstirred for 6 hours at room temperature, concentrated and purified bysilica gel column chromatography using ethyl acetate to afford theproducts (compounds 15a and 15b).

Compound 15a

30% yield. White powder, mp 161-163° C. ¹H NMR (C₅D₅N) δ 8.88 (1H, s),8.66 (1H, d, J=4.4 Hz), 8.21 (1H, s, NH), 7.98 (1H, d, J=8.0 Hz), 7.72(1H, d, J=7.6 Hz), 7.35 (1H, d, J=7.6 Hz), 7.31 (1H, dd, J=7.8, 2.0 Hz),7.23-7.12 (5H, m), 7.08 (1H, d, J=7.6 Hz), 6.85 (1H, d, J=6.8 Hz), 6.35(1H, d, J=8.0 Hz, NH), 4.95 (1H, ddd, J=14.4, 7.6, 7.6 Hz), 4.79 (1H,dd, J=13.6, 6.0 Hz), 3.63 (3H, s), 3.40 (1H, dd, J=14.4, 7.6 Hz), 3.23(1H, dd, J=14.4, 7.6 Hz), 2.93 (1H, dd, J=13.6, 6.0 Hz), 2.82 (1H, dd,J=13.6, 6.0 Hz). ¹³C NMR (C₅D₅N) δ 172.0 (s), 171.4 (s), 165.8 (s),152.7 (d), 148.6 (d), 136.6 (s), 136.0 (d), 135.6 (s), 129.9 (s), 129.5(2×C, d), 129.0 (2×C, d), 127.9 (s), 127.6 (d), 123.8 (d), 123.6 (d),122.8 (d), 120.3 (d), 119.1 (d), 111.8 (d), 110.7 (d), 54.8 (d), 53.7(d), 52.7 (q), 37.9 (t), 28.8 (t). ESI-MS (m/z, %): 471 [M+1]⁺ (100).HR-ESI-MS m/z 493.1850 [M+Na]⁺ (calcd for C₂₇H₂₆N₄O₄Na 493.1852).

Compound 15b

6% yield. White powder, mp 130-132° C. ¹H NMR (C₅D₅N) δ 8.88 (1H, s),8.69 (1H, d, J=4.0 Hz), 8.25 (1H, s, NH), 7.99 (1H, dd, J=6.0, 2.0 Hz),7.73 (1H, d, J=8.0 Hz), 7.35-7.31 (2H, m), 7.20 (1H, t, J=8.0 Hz),7.13-7.06 (6H, m), 6.85 (2H, d, J=6.8 Hz), 6.30 (1H, d, J=7.6 Hz, NH),4.92 (1H, dd, J=14.6, 7.6 Hz), 4.73 (1H, dd, J=13.6, 6.4 Hz), 3.65 (3H,s), 3.45 (1H, dd, J=14.6, 7.6 Hz), 3.21 (1H, dd, J=14.6, 7.6 Hz), 3.01(1H, dd, J=13.6, 6.4 Hz), 2.92 (1H, dd, J=13.6, 6.4 Hz). ¹³C NMR (C₅D₅N)δ 171.8 (s), 171.1 (s), 165.7 (s), 152.8 (d), 148.6 (d), 136.7 (s),135.9 (d), 135.5 (s), 129.9 (s), 129.5 (2×C, d), 128.9 (2×C, d), 127.8(s), 127.5 (d), 124.0 (d), 123.8 (d), 122.8 (d), 120.4 (d), 119.2 (d),111.8 (d), 110.7 (d), 54.5 (d), 53.9 (d), 52.7 (q), 38.2 (t), 28.7 (t).ESI-MS (m/z, %): 471 [M+1]⁺ (100). HR-ESI-MS m/z 493.1849 [M+Na]⁺ (calcdfor C₂₇H₂₆N₄O₄Na 493.1852).

Embodiment 4 General procedure for the synthesis ofN—(N-benzoyl-L-tryptophanyl)-para-substituted-D-phenylalanine methylesters (compounds 18a-23a and 18b-23b)

Para-Substituted-D-phenylalanine methyl esters (17a-17f) weresynthesized through deprotecting corresponding N-Boc-D-phenylalaninederivatives (16a-16f), respectively, in 20% trifluroacetic acid (TFA)solution (TFA-DCM=1:4), and then esterified through refluxing methanol(50 ml)—c-H₂SO₄ (1.0 ml) for 2 h. The resulting mixtures weresubsequently neutralized by ammonium water, partitioned between icewater (100 ml) and chloroform, and concentrated the organic layers.Subsequently, para-substituted-D-phenylalanine methyl esters (17a-17f,1.0 equiv.) and N-benzoyl-L-tryptophan (1.0 equiv.), which weresynthesized by a procedure similar to that described above, weredissolved in DCM, respectively, and then HBTU (2.0 equiv.) and DIEA (1.5equiv.) were added. The reaction mixture was stirred for 6 hours at roomtemperature, concentrated and purified by silica gel columnchromatography using a mixture of n-hexane-ethyl acetate (6:4) to affordthe products (compounds 18a-24a and 18b-24b).

N—(N-Benzoyl-L-tryptophanyl)-para-nitro-D-phenylalanine methyl esters(compounds 18a and 18b) Compound 18a

42% yield. White powder, mp 240-242° C. ¹H NMR (C₅D₅N) δ 11.91 (1H, s,NH), 9.76 (1H, d, J=8.0 Hz, NH), 9.24 (1H, d, J=8.0 Hz, NH), 8.09 (2H,d, J=8.0 Hz), 7.98 (2H, d, J=8.0 Hz), 7.90 (1H, d, J=8.0 Hz), 7.56 (1H,d, J=8.0 Hz), 7.45 (1H, s), 7.36 (1H, t, J=8.0 Hz), 7.30-7.24 (3H, m),7.17-7.14 (3H, m), 5.66 (1H, dd, J=14.2, 7.2 Hz), 5.31 (1H, dd, J=13.8,7.2 Hz), 3.80 (1H, dd, J=14.2, 7.2 Hz), 3.62 (1H, dd, J=14.2, 7.2 Hz),3.55 (3H, s), 3.22 (1H, dd, J=13.8, 7.2 Hz), 3.15 (1H, dd, J=13.8, 7.2Hz). ¹³C NMR (C₅D₅N) δ 172.8 (s), 171.7 (s), 167.9 (s), 147.1 (s), 145.4(s), 137.5 (s), 135.4 (s), 131.5 (d), 130.7 (2×C, d), 128.6 (s), 128.6(2×C, d), 128.1 (2×C, d), 124.5 (d), 123.7 (2×C, d), 121.9 (d), 119.4(d), 119.3 (d), 112.1 (d), 111.2 (s), 55.5 (d), 53.8 (d), 52.1 (q), 37.5(t), 28.9 (t). ESI-MS (m/z, %): 537 [M+Na]⁺ (100). HR-ESI-MS m/z537.1754 [M+Na]⁺ (calcd for C₂₈H₂₆N₄O₆Na 537.1750).

Compound 18b

8% yield. White powder, mp 182-184° C. ¹H NMR (C₅D₅N) δ 11.81 (1H, s,NH), 9.72 (1H, d, J=8.0 Hz, NH), 9.29 (1H, d, J=8.0 Hz, NH), 8.10 (2H,d, J=8.0 Hz), 7.97 (2H, d, J=8.0 Hz), 7.74 (1H, d, J=8.0 Hz), 7.49 (1H,d, J=8.0 Hz), 7.44 (1H, s), 7.41-7.37 (3H, m), 7.32 (2H, t, J=7.6 Hz),7.20 (1H, t, J=8.0 Hz), 7.05 (1H, t, J=8.0 Hz), 5.65 (1H, dd, J=14.8,7.2 Hz), 5.31 (1H, dd, J=13.6, 8.0 Hz), 3.77 (1H, dd, J=14.8, 7.2 Hz),3.62 (3H, s), 3.61 (1H, dd, J=14.8, 7.2 Hz), 3.39 (1H, dd, J=13.6, 8.0Hz), 3.21 (1H, dd, J=13.6, 8.0 Hz). ¹³C NMR (C₅D₅N) δ 173.0 (s), 171.9(s), 168.0 (s), 147.1 (s), 145.4 (s), 137.5 (s), 135.4 (s), 131.6 (d),130.9 (2×C, d), 128.6 (2×C, d), 128.5 (s), 128.1 (2×C, d), 124.4 (d),123.7 (2×C, d), 121.7 (d), 119.2 (d), 119.1 (d), 111.9 (d), 111.1 (s),55.3 (d), 53.7 (d), 52.2 (q), 37.8 (t), 28.5 (t). ESI-MS (m/z, %): 537[M+Na]⁺ (100). HR-ESI-MS m/z 537.1753 [M+Na]⁺ (calcd for C₂₈H₂₆N₄O₆Na537.1750).

N—(N-Benzoyl-L-tryptophanyl)-para-methyl-D-phenylalanine methyl esters(compounds 19a and 19b) Compound 19a

50% yield. White powder, mp 185-187° C. CD (c 0.18 mM, MeOH) nm (mdeg)232 (−1.30), 224 (−0.28) nm. ¹H NMR (C₅D₅N) δ 11.82 (1H, s, NH), 9.35(1H, d, J=8.0 Hz, NH), 9.07 (1H, d, J=8.0 Hz, NH), 8.04 (2H, d, J=8.0Hz), 7.87 (2H, d, J=8.0 Hz), 7.53 (1H, d, J=7.6 Hz), 7.36-7.34 (2H, m),7.28-7.20 (3H, m), 7.14 (1H, t, J=7.6 Hz), 7.08 (1H, d, J=7.6 Hz), 6.99(2H, d, J=7.6 Hz), 5.68 (1H, dd, J=14.4, 6.8 Hz), 5.22 (1H, dd, J=13.8,7.2 Hz), 3.80 (1H, dd, J=14.4, 6.8 Hz), 3.64 (1H, dd, J=14.4, 6.8 Hz),3.52 (3H, s), 3.16 (1H, dd, J=13.8, 7.2 Hz), 3.07 (1H, dd, J=13.8, 7.2Hz), 2.11 (3H, s). ¹³C NMR (C₅D₅N) δ 172.7 (s), 172.4 (s), 167.8 (s),137.5 (s), 135.4 (s), 134.3 (s), 131.4 (d), 129.7 (2×C, d), 129.5 (2×C,d), 128.7 (s), 128.5 (2×C, d), 128.0 (2×C, d), 124.4 (d), 121.8 (d),119.3 (2×C, d), 112.0 (d), 111.2 (s), 55.3 (d), 54.5 (d), 51.9 (q), 37.6(t), 29.0 (t), 20.9 (q). ESI-MS (m/z, %): 506 [M+Na]⁺ (100). HR-ESI-MSm/z 506.2059 [M+Na]⁺ (calcd for C₂₉H₂₉N₃O₄Na 506.2056).

Compound 19b

16% yield. White powder, mp 197-199° C. CD (c 0.18 mM, MeOH) nm (mdeg)233 (1.75), 221 (−1.81), 213 (−0.42) nm. ¹H NMR (C₅D₅N) δ 11.79 (1H, s,NH), 9.52 (1H, d, J=8.0 Hz, NH), 9.16 (1H, d, J=8.0 Hz, NH), 8.09 (2H,d, J=8.0 Hz), 7.78 (2H, d, J=8.0 Hz), 7.48 (1H, d, J=8.0 Hz), 7.46 (1H,d, J=1.6 Hz), 7.38 (1H, t, J=8.0 Hz), 7.30 (2H, t, J=8.0 Hz), 7.22-7.15(3H, m), 7.07 (1H, d, J=8.0 Hz), 6.92 (2H, d, J=7.6 Hz), 5.70 (1H, dd,J=14.4, 7.2 Hz), 5.24 (1H, dd, J=13.8, 7.2 Hz), 3.80 (1H, dd, J=14.4,7.2 Hz), 3.65 (1H, dd, J=14.4, 7.2 Hz), 3.58 (3H, s), 3.27 (1H, dd,J=13.8, 7.2 Hz), 3.14 (1H, dd, J=13.8, 7.2 Hz), 2.04 (3H, s). ¹³C NMR(C₅D₅N) δ 172.7 (s), 172.5 (s), 167.9 (s), 137.5 (s), 136.2 (s), 135.3(s), 134.3 (s), 131.4 (d), 129.7 (2×C, d), 129.4 (2×C, d), 128.7 (s),128.5 (2×C, d), 128.1 (2×C, d), 124.4 (d), 121.7 (d), 119.2 (2×C, d),111.9 (d), 111.2 (s), 55.1 (d), 54.6 (d), 51.9 (q), 37.8 (t), 28.6 (t),20.9 (q). ESI-MS (m/z, %): 506 [M+Na]⁺ (100). HR-ESI-MS m/z 506.2060[M+Na]⁺ (calcd for C₂₉H₂₉N₃O₄Na 506.2056).

N—(N-Benzoyl-L-tryptophanyl)-para-fluoro-D-phenylalanine methyl esters(compounds 20a and 20b) Compound 20a

45% yield. White powder, mp 178-180° C. CD (c 0.12 mM, MeOH) nm (mdeg)232 (−0.76), 223 (0.68) nm. ¹H NMR (C₅D₅N) δ 11.84 (1H, s, NH), 9.40(1H, d, J=7.6 Hz, NH), 9.15 (1H, d, J=7.6 Hz, NH), 8.07 (2H, d, J=7.6Hz), 7.90 (2H, d, J=7.6 Hz), 7.54 (1H, d, J=7.6 Hz), 7.40 (1H, s), 7.35(1H, t, J=7.2 Hz), 7.29-7.25 (3H, m), 7.25-7.20 (3H, m), 7.15 (1H, t,J=7.6 Hz), 7.08 (1H, d, J=6.4 Hz), 6.89 (2H, t, J=8.0 Hz), 5.68 (1H, dd,J=14.2, 6.8 Hz), 5.19 (1H, dd, J=13.6, 6.8 Hz), 3.79 (1H, dd, J=14.2,6.8 Hz), 3.65 (1H, dd, J=14.2, 6.8 Hz), 3.58 (3H, s), 3.27 (1H, dd,J=13.8, 6.8 Hz), 3.13 (1H, dd, J=13.6, 6.8 Hz). ¹³C NMR (C₅D₅N) δ 172.7(s), 172.1 (s), 167.9 (s), 162.1 (s, J_(C-F)=242.2 Hz), 137.5 (s), 135.4(s), 133.4 (s, J_(C-F)=3.0 Hz), 131.4 (d), 128.7 (s), 128.5 (2×C, d),128.1 (2×C, d), 124.4 (d), 121.9 (d), 119.3 (2×C, d), 115.4 (2×C, d,J_(C-F)=21.4 Hz), 112.0 (d), 111.2 (s), 55.4 (d), 54.4 (d), 51.9 (q),37.1 (t), 29.0 (t). ESI-MS (m/z, %): 510 [M+Na]⁺ (100). HR-ESI-MS m/z510.1808 [M+Na]⁺ (calcd for C₂₈H₂₆FN₃O₄Na 510.1805).

Compound 20b

14% yield. White powder, mp 184-186° C. CD (c 0.12 mM, MeOH) nm (mdeg)233 (0.69), 221 (−0.55) nm. ¹H NMR (C₅D₅N) δ 11.80 (1H, s, NH), 9.60(1H, d, J=8.0 Hz, NH), 9.22 (1H, d, J=8.0 Hz, NH), 8.11 (2H, d, J=7.6Hz), 7.77 (2H, d, J=7.6 Hz), 7.49 (1H, d, J=7.6 Hz), 7.46 (1H, s), 7.37(1H, t, J=7.6 Hz), 7.30 (1H, t, J=7.6 Hz), 7.25-7.20 (3H, m), 7.06 (1H,t, J=7.6 Hz), 6.89 (2H, t, J=8.0 Hz), 5.68 (1H, dd, J=14.6, 7.2 Hz),5.22 (1H, dd, J=13.8, 7.2 Hz), 3.79 (1H, dd, J=14.6, 7.2 Hz), 3.65 (1H,dd, J=14.6, 7.2 Hz), 3.58 (3H, s), 3.27 (1H, dd, J=13.8, 7.2 Hz), 3.13(1H, dd, J=13.8, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 172.8 (s), 172.3 (s), 167.9(s), 162.1 (s, J_(C-F)=242.0 Hz), 137.5 (s), 135.5 (s), 133.4 (s,J_(C-F)=3.2 Hz), 131.6 (d, JC-F=8.0 Hz), 131.5 (d), 128.6 (s), 128.5(2×C, d), 128.1 (2×C, d), 124.4 (d), 121.7 (d), 119.2 (d), 119.1 (d),115.4 (2×C, d, J_(C-F)=21.0 Hz), 111.9 (d), 111.2 (s), 55.2 (d), 54.4(d), 52.0 (q), 37.3 (t), 28.6 (t). ESI-MS (m/z, %): 510 [M+Na]⁺ (100).HR-ESI-MS m/z 510.1809 [M+Na]⁺ (calcd for C₂₈H₂₆FN₃O₄Na 510.1805).

N—(N-Benzoyl-L-tryptophanyl)-para-chloro-D-phenylalanine methyl esters(compounds 21a and 21b) Compound 21a

37% yield. White powder, mp 190-191° C. ¹H NMR (C₅D₅N) δ 11.86 (1H, s,NH), 9.42 (1H, d, J=8.0 Hz, NH), 9.16 (1H, d, J=8.0 Hz, NH), 8.07 (2H,d, J=8.0 Hz), 7.90 (1H, d, J=8.0 Hz), 7.54 (1H, d, J=7.6 Hz), 7.40 (1H,d, J=1.6 Hz), 7.35 (1H, t, J=7.2 Hz), 7.29-7.23 (3H, m), 7.19-7.14 (3H,m), 7.02 (2H, d, J=8.0 Hz), 5.68 (1H, dd, J=14.2, 7.2 Hz), 5.18 (1H, dd,J=14.0, 7.2 Hz), 3.79 (1H, dd, J=14.2, 7.2 Hz), 3.64 (1H, dd, J=14.2,7.2 Hz), 3.51 (3H, s), 3.11 (1H, dd, J=14.0, 7.2 Hz), 3.03 (1H, dd,J=14.0, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 172.7 (s), 172.0 (s), 167.9 (s),137.5 (s), 136.2 (s), 135.5 (s), 132.6 (s), 131.5 (2×C, d), 131.4 (2×C,d), 128.8 (2×C, d), 128.7 (s), 128.5 (2×C, d), 128.1 (2×C, d), 124.4(d), 121.9 (d), 119.3 (2×C, d), 112.0 (d), 111.2 (s), 55.4 (d), 54.2(d), 51.9 (q), 37.2 (t), 29.0 (t). ESI-MS (m/z, %): 526 [M+Na]⁺ (100).HR-ESI-MS m/z 526.1506 [M+Na]⁺ (calcd for C₂₈H₂₆ClN₃O₄Na 526.1509).

Compound 21b

9% yield. White powder, mp 174-176° C. ¹H NMR (C₅D₅N) δ 11.80 (1H, s,NH), 9.62 (1H, d, J=8.0 Hz, NH), 9.23 (1H, d, J=8.0 Hz, NH), 8.11 (2H,d, J=8.0 Hz), 7.77 (1H, d, J=8.0 Hz), 7.49 (1H, d, J=8.0 Hz), 7.46 (1H,br.s), 7.38 (1H, t, J=8.0 Hz), 7.31 (2H, t, J=8.0 Hz), 7.22-7.19 (3H,m), 7.14 (2H, t, J=8.0 Hz), 7.06 (1H, d, J=8.0 Hz), 5.68 (1H, dd,J=14.6, 7.2 Hz), 5.22 (1H, dd, J=13.8, 7.6 Hz), 3.79 (1H, dd, J=14.6,7.2 Hz), 3.64 (1H, dd, J=14.6, 7.2 Hz), 3.58 (3H, s), 3.26 (1H, dd,J=13.8, 7.6 Hz), 3.12 (1H, dd, J=13.8, 7.6 Hz). ¹³C NMR (C₅D₅N) δ 172.8(s), 172.2 (s), 168.0 (s), 137.5 (s), 136.3 (s), 135.5 (s), 132.5 (s),131.5 (d), 131.4 (2×C, d), 128.7 (s), 128.7 (2×C, d), 128.6 (2×C, d),124.4 (d), 121.7 (d), 119.2 (d), 119.1 (d), 111.9 (d), 111.2 (s), 55.2(d), 54.2 (d), 52.0 (q), 37.4 (t), 28.6 (t). ESI-MS (m/z, %): 526[M+Na]⁺ (100). HR-ESI-MS m/z 526.1511 [M+Na]⁺ (calcd for C₂₈H₂₆ClN₃O₄Na526.1509).

N—(N-Benzoyl-L-tryptophanyl)-para-bromo-D-phenylalanine methyl esters(compounds 22a and 22b) Compound 22a

23% yield. White powder, mp 190-191° C. CD (c 0.15 mM, MeOH) nm (mdeg)232 (−0.41), 223 (0.15) nm. ¹H NMR (C₅D₅N) δ 11.85 (1H, s, NH), 9.40(1H, d, J=8.0 Hz, NH), 9.12 (1H, d, J=8.0 Hz, NH), 8.07 (2H, d, J=7.2Hz), 7.90 (1H, d, J=7.6 Hz), 7.54 (1H, d, J=7.6 Hz), 7.41 (1H, br.s),7.38-7.32 (3H, m), 7.28 (1H, t, J=7.2 Hz), 7.24 (1H, t, J=7.6 Hz), 7.15(1H, t, J=8.0 Hz), 6.97 (2H, d, J=8.0 Hz), 5.67 (1H, dd, J=14.4, 7.2Hz), 5.17 (1H, dd, J=13.8, 7.2 Hz), 3.79 (1H, dd, J=14.4, 7.2 Hz), 3.64(1H, dd, J=14.4, 7.2 Hz), 3.51 (3H, s), 3.09 (1H, dd, J=13.8, 7.2 Hz),3.02 (1H, dd, J=13.8, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 172.7 (s), 172.0 (s),167.8 (s), 137.5 (s), 136.7 (s), 135.4 (s), 131.8 (2×C, d), 131.7 (2×C,d), 131.5 (d), 128.7 (s), 128.5 (2×C, d), 128.1 (2×C, d), 124.4 (d),121.9 (d), 120.9 (s), 119.3 (2×C, d), 112.0 (d), 111.2 (s), 55.4 (d),54.1 (d), 51.9 (q), 37.2 (t), 29.0 (t). ESI-MS (m/z, %): 570 [M+Na]⁺(100), 572 [M+2+Na]⁺ (100). HR-ESI-MS m/z 570.1008 [M+Na]⁺ (calcd forC₂₈H₂₆BrN₃O₄Na 570.1004).

Compound 22b

8% yield. White powder, mp 174-176° C. CD (c 0.18 mM, MeOH) nm (mdeg)241 (0.49), 232 (0.24), 220 (−0.75), 214 (−0.28) nm. ¹H NMR (C₅D₅N) δ11.81 (1H, s, NH), 9.62 (1H, d, J=8.0 Hz, NH), 9.23 (1H, d, J=8.0 Hz,NH), 8.11 (2H, d, J=8.0 Hz), 7.76 (1H, d, J=7.6 Hz), 7.49 (1H, d, J=7.6Hz), 7.45 (1H, d, J=1.6 Hz), 7.39 (1H, t, J=7.6 Hz), 7.32 (2H, t, J=7.6Hz), 7.29 (2H, d, J=7.2 Hz), 7.20 (1H, t, J=7.6 Hz), 7.14 (2H, d, J=8.4Hz), 7.06 (1H, t, J=7.6 Hz), 5.68 (1H, dd, J=14.6, 7.2 Hz), 5.21 (1H,dd, J=13.6, 7.6 Hz), 3.79 (1H, dd, J=14.6, 7.2 Hz), 3.64 (1H, dd,J=14.6, 7.2 Hz), 3.58 (3H, s), 3.24 (1H, dd, J=13.6, 7.6 Hz), 3.10 (1H,dd, J=13.6, 7.6 Hz). ¹³C NMR (C₅D₅N) δ 172.8 (s), 172.1 (s), 168.0 (s),137.5 (s), 136.8 (s), 135.5 (s), 131.8 (2×C, d), 131.7 (2×C, d), 131.5(d), 128.6 (s), 128.6 (s), 128.6 (2×C, d), 128.1 (2×C, d), 124.4 (d),121.7 (d), 120.9 (s), 119.2 (d), 119.1 (d), 111.9 (d), 111.2 (s), 55.2(d), 54.2 (d), 52.0 (q), 37.4 (t), 28.6 (t). ESI-MS (m/z, %): 570[M+Na]⁺ (100), 572 [M+2+Na]⁺ (100). HR-ESI-MS m/z 570.1007 [M+Na]⁺(calcd for C₂₈H₂₆BrN₃O₄Na 570.1004).

N—(N-Benzoyl-L-tryptophanyl)-para-trifluoromethyl-D-phenylalanine methylesters (compounds 23a and 23b) Compound 23a

26% yield. White powder, mp 233-235° C. ¹H NMR (C₅D₅N) δ 11.88 (1H, s,NH), 9.50 (1H, d, J=8.0 Hz, NH), 9.18 (1H, d, J=8.0 Hz, NH), 8.08 (2H,d, J=7.6 Hz), 7.89 (1H, d, J=7.6 Hz), 7.54 (1H, d, J=7.6 Hz), 7.45 (2H,d, J=8.0 Hz), 7.42 (1H, d, J=2.0 Hz), 7.36 (1H, t, J=7.6 Hz), 7.29-7.23(3H, m), 7.19 (2H, d, J=8.0 Hz), 7.15 (1H, t, J=7.6 Hz), 5.67 (1H, dd,J=14.4, 7.2 Hz), 5.23 (1H, dd, J=14.0, 7.2 Hz), 3.79 (1H, dd, J=14.4,7.2 Hz), 3.63 (1H, dd, J=14.4, 7.2 Hz), 3.52 (3H, s), 3.20 (1H, dd,J=14.0, 7.2 Hz), 3.14 (1H, dd, J=14.0, 7.2 Hz). ¹³C NMR (C₅D₅N) δ 172.8(s), 171.9 (s), 167.6 (s), 142.1 (s), 137.5 (s), 135.4 (s), 131.5 (d),130.4 (2×C, d), 128.7 (2×C, d), 128.6 (s, J_(C-F)=32.2 Hz), 128.1 (2×C,d), 125.5 (2×C, d, J_(C-F)=4.0 Hz), 125.0 (s, J_(C-F)=270.1 Hz), 124.4(d), 121.9 (d), 119.3 (2×C, d), 112.0 (d), 111.3 (s), 55.4 (d), 54.0(d), 52.0 (q), 37.5 (t), 29.0 (t). ESI-MS (m/z, %): 560 [M+Na]⁺ (100).HR-ESI-MS m/z 560.1776 [M+Na]⁺ (calcd for C₂₉H₂₆F₃N₃O₄Na 560.1773).

Compound 23b

9% yield. White powder, mp 187-189° C. ¹H NMR (C₅D₅N) δ 11.81 (1H, s,NH), 9.72 (1H, d, J=8.0 Hz, NH), 9.25 (1H, d, J=8.0 Hz, NH), 8.12 (2H,d, J=8.0 Hz), 7.75 (1H, d, J=8.0 Hz), 7.49 (1H, d, J=8.0 Hz), 7.44 (1H,d, J=2.0 Hz), 7.43 (2H, d, J=8.0 Hz), 7.40-7.37 (3H, m), 7.31 (2H, d,J=8.0 Hz), 7.20 (1H, t, J=8.0 Hz), 7.05 (1H, t, J=8.0 Hz), 5.67 (1H, dd,J=14.4, 7.2 Hz), 5.25 (1H, dd, J=14.0, 7.2 Hz), 3.78 (1H, dd, J=14.4,7.2 Hz), 3.62 (1H, dd, J=14.4, 7.2 Hz), 3.60 (3H, s), 3.36 (1H, dd,J=13.6, 8.0 Hz), 3.21 (1H, dd, J=13.6, 8.0 Hz). ¹³C NMR (C₅D₅N) δ 172.9(s), 172.0 (s), 168.0 (s), 142.2 (s), 137.5 (s), 135.4 (s), 131.5 (d),130.5 (2×C, d), 128.6 (2×C, d), 128.5 (s, J_(C-F)=32.0 Hz), 128.1 (2×C,d), 125.5 (2×C, d, J_(C-F)=4.0 Hz), 124.9 (s, J_(C-F)=270.0 Hz), 124.4(d), 121.9 (d), 119.2 (d), 119.1 (d), 111.9 (d), 111.1 (s), 55.4 (d),54.0 (d), 52.0 (q), 37.5 (t), 29.0 (t). ESI-MS (m/z, %): 560 [M+Na]⁺(100). HR-ESI-MS m/z 560.1775 [M+Na]⁺ (calcd for C₂₉H₂₆F₃N₃O₄Na560.1773).

Preparation of N—(N-benzoyl-L-tryptophanyl)-3-cyclohexyl-D-alaninemethyl esters (compounds 24a and 24b)

Compounds 24a and 24b were synthesized in 39% and 14%, respectively,yield from 3-cyclohexyl-D-alanine (16 g) by a similar procedure asdescribed above.

Compound 24a

White powder, mp 170-172° C. ¹H NMR (C₅D₅N) δ 11.88 (1H, s, NH), 9.45(1H, d, J=8.0 Hz, NH), 9.07 (1H, d, J=8.0 Hz, NH), 8.08 (2H, d, J=8.4Hz), 7.94 (1H, d, J=7.6 Hz), 7.56 (1H, d, J=7.6 Hz), 7.50 (1H, br.s),7.35 (1H, dt, J=7.6, 1.2 Hz), 7.29-7.23 (3H, m), 7.14 (1H, t, J=7.6 Hz),5.72 (1H, dd, J=14.2, 7.2 Hz), 5.00 (1H, m), 3.86 (1H, dd, J=14.2, 7.2Hz), 3.72 (1H, dd, J=14.2, 7.2 Hz), 3.58 (3H, s), 1.77 (1H, m), 1.66(2H, m), 1.59-1.48 (4H, m), 1.38 (1H, m), 1.25-0.96 (3H, m), 0.84-0.71(2H, m). ¹³C NMR (C₅D₅N) δ 173.7 (s), 172.9 (s), 167.7 (s), 137.5 (s),135.5 (s), 131.4 (s), 128.7 (s), 128.5 (2×C, d), 128.0 (2×C, d), 124.3(d), 121.8 (d), 119.3 (d), 119.2 (d), 112.0 (d), 111.2 (d), 55.4 (d),51.9 (q), 50.9 (d), 39.4 (t), 34.1 (d), 33.6 (t), 32.4 (t), 29.2 (t),26.6 (t), 26.3 (t), 26.1 (t). ESI-MS (m/z, %): 498 [M+Na]⁺ (100).HR-ESI-MS m/z 498.2366 [M+Na]⁺ (calcd for C₂₈H₃₃N₃O₄Na 498.2369).

Compound 24b

White powder, mp 109-111° C. ¹H NMR (C₅D₅N) δ 11.82 (1H, s, NH), 9.67(1H, d, J=8.0 Hz, NH), 9.27 (1H, d, J=8.0 Hz, NH), 8.12 (2H, d, J=8.0Hz), 7.78 (1H, d, J=7.6 Hz), 7.55 (1H, br.s), 7.49 (1H, d, J=7.6 Hz),7.35 (1H, dt, J=1.2, 8.0 Hz), 7.28 (2H, dt, J=1.2, 8.0 Hz), 7.20 (1H, t,J=7.6 Hz), 7.06 (1H, t, J=7.6 Hz), 5.71 (1H, dd, J=14.6, 7.6 Hz), 5.12(1H, dd, J=14.6, 7.6 Hz), 3.86 (1H, dd, J=14.6, 7.2 Hz), 3.71 (1H, dd,J=14.6, 7.2 Hz), 3.65 (3H, s), 1.73 (2H, m), 1.63 (1H, m), 1.54-1.41(5H, m), 1.13-0.92 (3H, m), 0.85-0.70 (2H, m). ¹³C NMR (C₅D₅N) δ 173.9(s), 173.0 (s), 167.8 (s), 137.5 (s), 135.5 (s), 131.4 (s), 128.7 (s),128.5 (2×C, d), 128.1 (2×C, d), 124.4 (d), 121.7 (d), 119.2 (2×C, d),111.9 (d), 111.2 (d), 55.3 (d), 52.0 (q), 50.8 (d), 39.7 (t), 34.2 (d),33.7 (t), 32.3 (t), 28.6 (t), 26.6 (t), 26.3 (t), 26.1 (t). ESI-MS (m/z,%): 498 [M+Na]⁺ (100). HR-ESI-MS m/z 498.2367 [M+Na]⁺ (calcd forC₂₈H₃₃N₃O₄Na 498.2369).

Preparation ofN—(N-benzoyl-L-tryptophanyl)-D-phenylalanine-glycine-nitriles (compounds27a and 27b)

To a mixture solution of Boc-phenylalanine (1.0 equiv.) andaminoacetonitrile (1.0 equiv.) in DCM was added HBTU (2.0 equiv.) andDIEA (1.5 equiv.). The reaction mixture was stirred at room temperaturefor 6.0 h, and then deprotected and purified by silica gel columnchromatography using a mixture of MeOH— CHC13 (1:10) to affordD-phenylalanine-glycine-nitrile (26). Compound 26 (1.0 equiv.) andN-benzoyl-L-tryptophan (1.0 equiv.) were dissolved in DCM, and then HBTU(2.0 equiv.) and DIEA (1.5 equiv.) were added. The reaction mixture wasstirred for 6 hours at room temperature, concentrated and purified bysilica gel column chromatography using ethyl acetate-n-hexane (1:1) toafford the mixture of 27a and 27b. The mixture was further purified byHPLC (mobile phase: 65% MeOH+0.03% TFA) to afford products.

Compound 27a

49% yield. White powder, mp 167-169° C. ¹H NMR (C₅D₅N) δ 11.81 (1H, s,NH), 9.73 (1H, t, J=5.6 Hz, NH), 9.63 (1H, d, J=8.4 Hz, NH), 8.39 (1H,d, J=6.4 Hz, NH), 8.07 (2H, d, J=7.6 Hz), 7.77 (1H, d, J=8.0 Hz), 7.56(1H, d, J=8.0 Hz), 7.35 (1H, t, J=7.6 Hz), 7.29-7.23 (5H, m), 7.20-7.18(3H, m), 7.15-7.09 (2H, m), 5.35-5.29 (2H, m), 5.00 (1H, m), 4.47 (2H,d, J=5.6 Hz), 3.70 (1H, dd, J=14.2, 7.6 Hz), 3.61 (1H, dd, J=14.2, 7.6Hz), 3.33 (1H, dd, J=13.6, 8.0 Hz), 3.09 (1H, dd, J=13.6, 8.0 Hz). ¹³CNMR (C₅D₅N) δ 173.2 (s), 172.7 (s), 166.8 (s), 138.1 (s), 137.5 (s),135.5 (s), 131.7 (s), 129.7 (2×C, d), 128.8 (2×C, d), 128.5 (s), 128.5(2×C, d), 128.2 (2×C, d), 126.9 (d), 124.5 (d), 121.9 (d), 119.3 (d),119.1 (d), 117.6 (s), 112.0 (s), 110.9 (s), 56.6 (d), 55.0 (d), 37.8(t), 28.4 (t), 28.0 (t). ESI-MS (m/z, %): 516 [M+Na]⁺ (100). HR-ESI-MSm/z 516.2008 [M+Na]⁺ (calcd for C₂₉H₂₇N₅O₃Na 516.2011).

Compound 27b

7% yield. White powder, mp 195-197° C. ¹H NMR (C₅D₅N) δ 11.80 (1H, s,NH), 9.76 (1H, d, J=8.0 Hz, NH), 9.63 (1H, t, J=5.2 Hz, NH), 9.10 (1H,d, J=7.6 Hz, NH), 8.07 (2H, d, J=8.0 Hz), 7.74 (1H, d, J=8.0 Hz), 7.49(1H, d, J=8.0 Hz), 7.44 (1H, br.s), 7.37 (1H, t, J=7.2 Hz), 7.31-7.25(4H, m), 7.18-7.14 (3H, m), 7.10-7.04 (2H, m), 5.59 (1H, dd, J=14.2, 7.2Hz), 5.18 (1H, dd, J=14.2, 7.2 Hz), 4.43 (1H, dd, J=17.2, 5.6 Hz), 4.32(1H, dd, J=17.2, 5.6 Hz), 3.74 (1H, dd, J=14.2, 7.6 Hz), 3.62 (1H, dd,J=14.2, 7.6 Hz), 3.41 (1H, dd, J=13.6, 8.0 Hz), 3.18 (1H, dd, J=13.6,8.0 Hz). ¹³C NMR (C₅D₅N) δ 172.7 (s), 172.5 (s), 168.0 (s), 137.9 (s),137.4 (s), 135.5 (s), 131.5 (s), 129.8 (2×C, d), 128.8 (2×C, d), 128.6(s), 128.5 (2×C, d), 128.1 (2×C, d), 126.9 (d), 124.5 (d), 121.7 (d),119.2 (d), 119.1 (d), 117.5 (s), 112.0 (s), 111.0 (s), 55.4 (d), 55.3(d), 38.4 (t), 28.5 (t), 27.8 (t). ESI-MS (m/z, %): 516 [M+Na]⁺ (100).HR-ESI-MS m/z 516.2008 [M+Na]⁺ (calcd for C₂₉H₂₇N₅O₃Na 516.2011).

Embodiments 6-12 are applications of various activity tests for eachdipeptide derivative, such as the evaluation of the inhibition ofelastase release and superoxide anion generation induced by specificactivators of FPR1, fMLP and specific activators of FPR2, formyl peptidereceptor-like 1 agonist (WKYMVm), as well as other related studies onthe pharmacological mechanism. The methods and procedures for activitytests and the results are as follows.

Embodiment 6 Cytotoxic Test

FIGS. 1( a)-1(b) show the influences of HCH6-1 on releasing lactatedehydrogenase (LDH) from human neutrophils under the followingexperimental conditions. The suspension of neutrophils was reacted withdifferent concentrations of candidate compounds for 15 min, or fixedconcentrations of candidate compounds for various times. Also, 0.1%Triton X-100 was added to react for 30 min as a release amount of totallactate dehydrogenase (Total LDH), wherein the supernatant was subjectedto centrifugation for 8 min, at 200 g and at 4° C., and then a lactatedehydrogenase reagent was added and kept in the dark and at roomtemperature for 30 min, and an absorbance at 492 nm was monitored.Results are measured based on Total LDH as 100%.

FIG. 1( a) shows that HCH6-1's inhibitory effects on fMLP-inducedsuperoxide anion generation and elastase release of neutrophils were notthe results of toxicity to the neutrophils.

FIG. 1( b) shows that there was no significant toxicity for HCH6-1 (30μM) treatment of the cells during a long period, such as 120 min, so asto demonstrate that high concentrations of HCH6-1 reacting with thecells for 120 min was non-toxic for the cells.

Embodiment 7 Evaluation of Inhibitory Effects on fMLP-Induced SuperoxideAnion Generation and Elastase Release of Human Neutrophils

Preparation of Human Neutrophils

Blood was taken from healthy human donors (20-32 years old) byvenipuncture, following a protocol approved by the Institutional ReviewBoard at Chang Gung Memorial Hospital. Neutrophils were isolated by astandard method of dextran sedimentation prior to centrifugation in aFicoll Hypaque gradient and the hypotonic lysis of erythrocytes.Purified neutrophils that contained >98% viable cells, as determined bythe trypan blue exclusion method, were resuspended in Ca²⁺-free HBSSbuffer at pH 7.4 and maintained at 4° C. before use.

Measurement of O₂ ^(•-) Generation

The evaluation of O₂ ^(•-) generation was based on the SOD-inhibitablereduction of ferricytochrome c. In brief, after supplementation with 0.5mg ml⁻¹ ferricytochrome c and 1 mM Ca²⁺, neutrophils were equilibratedat 37° C. for 2 min and incubated with drugs for min. Cells wereactivated with formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP, 30 nM)or Trp-Lys-Tyr-Met-Val-DMet (WKYMVm, 1.5 nM) for 10 min in thepre-process of cytochalasin B (CB, 1 μg ml⁻¹) for 3 min. Changes inabsorbance with the reduction of ferricytochrome c at 550 nm werecontinuously monitored in a double-beam, six-cell positionerspectrophotometer with constant stirring (Hitachi U-3010, Tokyo, Japan).Calculations were based on the differences in the reactions with andwithout SOD (100 U ml⁻¹) divided by the extinction coefficient for thereduction of ferricytochrome c (ε=21.1 mM⁻¹/10 mm)

Embodiment 8 Measurement of Elastase Release

The degranulation of azurophilic granules was determined by elastaserelease as described above. Experiments were performed usingMeO-Suc-Ala-Ala-Pro-Val-p-nitroanilide as the elastase substrate.Briefly, after supplementation withMeO-Suc-Ala-Ala-Pro-Val-p-nitroanilide (100 μM), neutrophils (6×10⁵ ml¹)were equilibrated at 37° C. for 2 min and incubated with drugs for 5min. Cells were activated by 30 nM fMLF or 1.5 nM WKYMVm for 10 min inthe pre-process of 0.5 μg ml⁻¹ CB for 3 min, and changes in absorbanceat 405 nm were continuously monitored to assay the elastase release. Theresults are expressed as the percentage of elastase release in thedrug-free control group.

Embodiment 9 Expression of CD11b on the Cell's Surface

The suspension of neutrophils was mixed at 37° C. and pre-heated for 5min, and then compounds with different concentrations for measurementswere added. After that, CB with 1 μg ml⁻¹ was added to react for 3 min,and subsequently fMLF with 30 nM is added to react for 10 min. And thereaction termination is done by on-ice setting. The supernatant wasremoved after centrifugation, and make the cells suspension again in thebalanced salt solution containing bovine serum albumin (BSA). Anti-CD11bwith fluorescein isothiocyanate (FITC) labeling was added, and kept onice and in the dark. Finally, a balanced salt solution was added toterminate the reaction. By means of the flow cytometer for detecting theanti-CD11b with fluorescein isothiocyanate (FITC) labeling, it ispossible to further evaluate whether the candidate compounds hadinfluence on CD11b expression on the cell membranes of activatedneutrophils according to changes in fluorescence. The experimentalresults showed that the HCH6-1 concentration is correlated to theinhibition of CD11b expression on cell membranes under the stimulus offMLF, while IC₅₀ was 0.26±0.05 μM, as shown in FIGS. 2( a) and 2(b).However, there was no inhibitory effects for HCH6-1 under the stimuli ofLeu-Glu-Ser-Ile-Phe-Arg-Ser-Leu-Leu-Phe-Arg-Val-Met (MMK1) and IL-8 (100nM), as shown in FIGS. 2( h) and 2(n).

Embodiment 10 Receptor Test

Membranes of human neutrophils contain fMLF receptor, formyl peptidereceptor 1 (FPR1), with which formyl-NIe-Leu-Phe-NIe-Tyr-Lys (FNLFNYK)carrying the fluorescence property was combined with FPR1 and competedwith the candidate compound for receptor binding. Therefore, by bindingwith the receptor, it was possible to further clarify whether thecompound interacts with the receptor. FIGS. 3( a)-3(h) showed theinhibition of HCH6-1 regarding the effect of FNLFNYK combined with FPR1on the membranes of human neutrophils. The experimental results showedthat the HCH6-1 concentration was correlated to the inhibition ofFNLFNYK bound to FPR1, while IC₅₀ was 2.02±0.34 μM.

Embodiment 11 Western Blot

Mitogen-activated protein kinases (MAPKs) and the expression of Aktphosphorylation are closely related to the regulation of cellinflammatory response. By specific binding of antibodies, eachcompound's influence on protein expression activated by differentsignals was observed. As to neutrophils, MAPKs (ERK, p38, and INK) andAkt signal transduction pathways are involved in the regulation ofsuperoxide anion generation and elastase release. It is can be seen fromthe above-mentioned experiments that HCH6-1 is capable of competitivelyinhibiting superoxide anion generation and elastase release. Whetherdownstream MAPKs and Akt signal transduction pathways of FPR1 wereinvolved in the regulation of superoxide anion generation and elastaserelease is explored below.

FIGS. 4( a)-4(d) showed the capability of HCH6-1 to significantlyinhibit phosphorylation for MAPKs (ERK, p38 and INK) and Akt. Theexperimental conditions were as follows. HCH6-1 (10 μM) waspre-processed for 5 min, followed by stimulus of fMLF (3-30 nM) for 30sec. The experimental results showed that HCH6-1 inhibited signaltransductions of MAPKs and Akt in cells. With a low concentrationstimulus of fMLF (3 nM), HCH6-1 significantly suppressed phosphorylationfor MAPKs and Akt, and thus an indirect proof for the competitivecapability is provided, as shown in FIGS. 4( a)-4(d).

Embodiment 12 Statistical Analysis

Results are expressed as the mean±SEM. Data were analyzed using GraphPadPrism software (GraphPad Software, San Diego, Calif.). Statisticalanalysis was performed using a Student's t-test or one-way analysis ofvariance (ANOVA), followed by a Tukey range test. A value of p<0.05 wasconsidered statistically significant.

In conclusion, the present invention utilizes simple synthesizingmethods to generate a series of dipeptide derivatives, in which twoamino acids need to be L (5) and D (R) configurations respectively, andthe N-terminal and C-terminal are substituted. It was found that thisseries of compounds excellently suppresses superoxide anion generationand elastase release of human neutrophils in the experimental mode whichwere induced by specific activators of FPR1, fMLF. Although superoxideanion generation and elastase release of human neutrophils induced byspecific activators of FPR2, WKYMVm were also suppressed, there was asignificant decrement by 3-20 fold compared to the inhibition induced byspecific activators of FPR1. It is shown that this novel series ofpeptide derivatives selectively antagonizes against FPR1.

More specifically, compound 3 (HCH6-1) has only slight influencewhenever it is triggered by non-FPR1 activation. Interestingly, compound3 (HCH6-1) competitively inhibited the downstream signal transductionpathways of FPR1, including calcium, MAPKs and Akt. By integrating theexperimental results, it can be deduced that compound 3 (HCH6-1)selectively and competitively inhibits FPR1 to activate humanneutrophils. Under this hypothesis, HCH6-1 is capable of inhibiting thecombination of N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, one kind ofFPR-like fluorescein derivative, with FPR1. In Human neutrophils,compound 3 (HCH6-1) is capable of competitively inhibiting FPR1.

In addition, during the synthesizing process of dipeptide derivatives,two isomers containing (E)-N-benzoyl or (Z)-N-benzoyl substitutes inN-terminals can be obtained. Analytical results of the CircularDichroism Spectrum regarding the compounds shows that the value ofCotton Effect at wavelength 220 nm is negative for dipeptide derivativescontaining (E)-N-benzoyl, while the corresponding value at wavelength220 nm is positive for dipeptide derivatives containing (Z)-N-benzoyl.In activity evaluation, dipeptide derivatives containing the(Z)-N-benzoyl group are superior to those containing the (E)-N-benzoylgroup.

The results show that compounds 1 and 24a selectively and competitivelyinhibits the FPR1-induced human neutrophil activation. Consistent withthe hypothesis, compound 1 inhibited the binding ofN-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, a fluorescent analogue offMLP, to FPR. Considering the importance of N-formyl peptides inflammatory processes, our data indicate that these dipeptides may havetherapeutic potential to attenuate neutrophil-mediated inflammatorydiseases by blocking FPR1.

Embodiments

-   1. A method for treating a neutrophil inflammatory disorder with an    antagonist of formyl peptide receptor 1 (FPR1), comprising:

providing a derivative of N—(N-aroyl-L-tryptophanyl)-D-phenylalaninerepresented by formula (I), wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively; each of RK and RT is selected from a group        consisting of a hydrogen, a hydroxyl group, a C₁-C₄ alkyl-        hydroxyl substituted (C₁-C₄ alkyl-OH) group, a C₁-C₄ alkoxyl        group, a carboxylic acid group, a C₁-C₄ alkyl        nitrile-substituted (CONHC₁-C₄alkyl-CN) group, or C₁-C₄        alkyl-substituted (CONHC₁-C₄ alkyl) or C₁-C₄ alkoxyl-substituted        (CONHC₁-C₄ alkoxyl) amido group, a C₁-C₄ alkyl-substituted ester        (COOC₁-C₄ alkyl) group and a benzoyl group having a C₁-C₄        alkyl-substituted benzene ring; and    -   each of RM and RS is selected from a group consisting of a        hydrogen, a hydroxyl group, a phenyl group, a pyridinyl group, a        carboxylic acid group, a C₁-C₄ alkoxyl substituted ester group,        and a benzoyl group having a hydroxyl-substituted, a        halogen-substituted, a C₁-C₄ alkoxyl-substituted or a C₁-C₄        alkyl-substituted benzene ring.

-   2. The method of Embodiment 1, further comprising providing one    selected from a group consisting of a pharmaceutically acceptable    salt, solvate and combination thereof for formula (I).-   3. The method of any one of Embodiments 1-2, wherein the neutrophil    inflammatory disorder is selected from a group consisting of lung    injury, chronic obstructive pulmonary disease, acute respiratory    distress syndrome, asthma, ischemic reperfusing injury, arthritis    and septicemia.-   4. A dipeptide derivative represented by formula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively; each of RK and RT is selected from a group        consisting of a hydrogen, a hydroxyl group, a C₁-C₄        alkyl-substituted hydroxyl group, a C₁-C₄ alkoxyl group, a        carboxylic acid group, a C₁-C₄ alkyl nitrile-substituted, C₁-C₄        alkyl-substituted or C₁-C₄ alkoxyl-substituted amido group, a        C₁-C₄ alkyl-substituted ester group and a benzoyl group having a        C₁-C₄ alkyl-substituted benzene ring; and    -   each of RM and RS is selected from a group consisting of a        hydrogen, a hydroxyl group, a phenyl group, a pyridinyl group, a        carboxylic acid group, a C₁-C₄ alkoxyl substituted ester group,        and a benzoyl group having a hydroxyl-substituted, a        halogen-substituted, a C₁-C₄ alkoxyl-substituted or a C₁-C₄        alkyl-substituted benzene ring.

-   5. The dipeptide derivative of Embodiment 4, wherein the halogen is    one selected from a group consisting of fluorine (F), chlorine (Cl),    bromine (Br) and iodine (I).

-   6. The dipeptide derivative of any one of Embodiments 4-5 inhibits    and antagonizes a formyl peptide receptor 1.

-   7. A dipeptide derivative represented by formula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively;    -   RK is selected from a hydrogen; RS is selected from a        methylphenyl group;    -   RM is selected from a phenyl group; and    -   RT is selected from C₁-C₄ alkoxyl-substituted ester group.

-   8. The dipeptide derivative of Embodiment 7 inhibits and antagonizes    a formyl peptide receptor 1.

-   9. A dipeptide derivative represented by formula (I),

wherein:

-   -   the chiral centers in formula (I) are S and R configurations        respectively;    -   RK is selected from a hydrogen;    -   RS is selected from a methyl-C₆-cycloalkyl group;    -   RM is selected from a phenyl group; and    -   RT is selected from C₁-C₄ alkyl-substituted ester group.

-   10. The dipeptide derivative of Embodiment 9, further comprising a    pharmaceutically acceptable salt, solvate or combination thereof

-   11. A method for treating a neutrophil inflammatory disorder with an    antagonist of formyl peptide receptor 1 (FPR1), comprising:

providing a derivative of N—(N-aroyl-L-tryptophanyl)-D-phenylalaninemethyl esters represented by formula (II), wherein:

the chiral centers in formula (II) are S and R configurationsrespectively;

R₁ is one selected from a group consisting of a hydrogen, a hydroxylgroup and a methoxy group;

R₂ is one selected from a group consisting of a non-substituted phenylgroup, a mono-substituted phenyl group, a di-substituted phenyl group,or a tri-substituted phenyl group, a pyridinyl group and a C₄-C₆cycloalkyl group;

R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is one selected from a group consisting of a hydroxyl, a C1-C4alkoxyl and a glycin-nitrile groups.

-   12. A method for treating a neutrophil inflammatory disorder with an    antagonist of FPR1, comprising:    provide a derivative of N—(N-aroyl-L-tryptophanyl)-D-phenylalanine    methyl esters represented by formula (II), wherein:

wherein the chiral centers in formula (II) are S and R configurationsrespectively;

R₁ is one selected from a group consisting of a hydrogen, a hydroxylgroup and a methoxy group;

R₂ is one selected from a group consisting of a non-substituted phenylgroup, a mono-substituted phenyl group, a di-substituted phenyl group,or a tri-substituted phenyl, a pyridinyl and a C₄-C₆ cycloalkyl groups;

R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is one selected from a group consisting of a hydroxyl group, a C1-C4alkoxyl group and a glycin-nitrile group.

-   13. The method of Embodiment 12, further comprising providing one    selected from a group consisting of a pharmaceutically acceptable    salt, solvate and combination thereof for formula (II).-   14. The method of any one of Embodiments 12-13, wherein the    neutrophil inflammatory disorder is selected from a group consisting    of lung injury, chronic obstructive pulmonary disease, acute    respiratory distress syndrome, asthma, ischemic reperfusing injury,    arthritis and septicemia.-   15. A dipeptide derivative represented by formula (II),

wherein:

the chiral centers in formula (II) are S and R configurationsrespectively; R₁ is selected from one of a hydrogen and a hydroxylgroup;

R₂ is one selected from a group consisting of non-substituted phenylgroup, mono-substituted phenyl group, di-substituted phenyl group, ortri-substituted phenyl group and pyridinyl group;

R₃ is one selected from a group consisting of a non-substituted benzoylgroup, a mono-substituted benzoyl group, a di-substituted benzoyl groupand a tri-substituted benzoyl group; and

R₄ is selected from one of C1-C4 alkoxyl group and a glycin-nitrilegroup.

-   16. The dipeptide derivative of Embodiment 15 inhibits and    antagonizes a FPR1.-   17. The dipeptide derivative of any one of Embodiments 15-16    inhibits a fMLP's derivative    N-Formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein FNLFNYK binding to the    FPR1.-   18. The dipeptide derivative of any one of Embodiments 15-17    inhibits at least one selected from a group consisting of FPR1    downstream, calcium, MAPKs and Akt.-   19. The dipeptide derivative of any one of Embodiments 15-18,    wherein the dipeptide derivative competitively inhibits superoxide    anion generation and neutrophil elastase release induced by a FPR1    activator.-   20. The dipeptide derivative of any one of Embodiments 15-19,    wherein the FPR1 activator is derived from a neutrophil inflammatory    disorder and the neutrophil inflammatory disorder is selected from a    group consisting of following diseases or symptoms: lung injury,    chronic obstructive pulmonary disease, acute respiratory distress    syndrome, asthma, ischemic reperfusing injury, arthritis and    septicemia.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiments. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A method for treating neutrophil inflammatorydisorders with an antagonist of formyl peptide receptor 1 (FPR1),comprising: providing a derivative ofN—(N-aroyl-L-tryptophanyl)-D-phenylalanine represented by formula (I),wherein: the chiral centers in formula (I) are S and R configurationsrespectively; each of RK and RT is selected from a group consisting of ahydrogen, a hydroxyl group, a C₁-C₄ alkyl-hydroxyl substituted (C₁-C₄alkyl-OH) group, a C₁-C₄ alkoxyl group, a carboxylic acid group, a C₁-C₄alkyl nitrile-substituted (CONHC₁-C₄alkyl-CN) group, or C₁-C₄alkyl-substituted (CONHC₁-C₄ alkyl) or C₁-C₄ alkoxyl-substituted(CONHC₁-C₄ alkoxyl) amido group, a C₁-C₄ alkyl-substituted ester(COOC₁-C₄ alkyl) group and a benzoyl group having a C₁-C₄alkyl-substituted benzene ring; and each of RM and RS is selected from agroup consisting of a hydrogen, a hydroxyl group, a phenyl group, apyridinyl group, a carboxylic acid group, a C₁-C₄ alkoxyl substitutedester group, and a benzoyl group having a hydroxyl-substituted, ahalogen-substituted, a C₁-C₄ alkoxyl-substituted or a C₁-C₄alkyl-substituted benzene ring.


2. The method as claimed in claim 1, further comprising providing oneselected from a group consisting of a pharmaceutically acceptable salt,solvate and combination thereof for formula (I).
 3. The method asclaimed in claim 1, wherein the neutrophil inflammatory disorders areselected from a group consisting of lung injury, chronic obstructivepulmonary disease, acute respiratory distress syndrome, asthma, ischemicreperfusing injury, arthritis and septicemia.
 4. A dipeptide derivativerepresented by formula (I),

wherein: the chiral centers in formula (I) are S and R configurationsrespectively; each of RK and RT is selected from a group consisting of ahydrogen, a hydroxyl group, a C₁-C₄ alkyl-substituted hydroxyl group, aC₁-C₄ alkoxyl group, a carboxylic acid group, a C₁-C₄ alkylnitrile-substituted, C₁-C₄ alkyl-substituted or C₁-C₄alkoxyl-substituted amido group, a C₁-C₄ alkyl-substituted ester groupand a benzoyl group having a C₁-C₄ alkyl-substituted benzene ring; andeach of RM and RS is selected from a group consisting of a hydrogen, ahydroxyl group, a phenyl group, a pyridinyl group, a carboxylic acidgroup, a C₁-C₄ alkoxyl substituted ester group, and a benzoyl grouphaving a hydroxyl-substituted, a halogen-substituted, a C₁-C₄alkoxyl-substituted or a C₁-C₄ alkyl-substituted benzene ring.
 5. Thedipeptide derivative as claimed in claim 4, wherein the halogen is oneselected from a group consisting of fluorine (F), chlorine (Cl), bromine(Br) and iodine (I).
 6. The dipeptide derivative as claimed in claim 4inhibits and antagonizes a formyl peptide receptor
 1. 7. A dipeptidederivative represented by formula (II),

wherein: the chiral centers in formula (II) are S and R configurationsrespectively; R₁ is selected from one of a hydrogen and a hydroxylgroup; R₂ is one selected from a group consisting of non-substitutedphenyl group, mono-substituted phenyl group, di-substituted phenylgroup, or tri-substituted phenyl group and pyridinyl group; R₃ is oneselected from a group consisting of a non-substituted benzoyl group, amono-substituted benzoyl group, a di-substituted benzoyl group and atri-substituted benzoyl group; and R₄ is selected from one of C1-C4alkoxyl group and a glycin-nitrile group.
 8. The dipeptide derivative asclaimed in claim 7 inhibits and antagonizes a formyl peptide receptor 1.9. The dipeptide derivative as claimed in claim 8 inhibits at least oneselected from a group consisting of FPR1 downstream, calcium,mitogen-activated protein kinases and protein kinase B.
 10. Thedipeptide derivative as claimed in claim 8, wherein the dipeptidederivative competitively inhibits superoxide anion generation andneutrophil elastase release induced by a FPR1 activator.
 11. Thedipeptide derivative as claimed in claim 10, wherein the FPR1 activatoris derived from neutrophil inflammatory disorders and the neutrophilinflammatory disorder is selected from a group consisting of followingdiseases or symptoms: lung injury, chronic obstructive pulmonarydisease, acute respiratory distress syndrome, asthma, ischemicreperfusing injury, arthritis and septicemia.